image • David Leonard - Computer Support in London

iPhone Photo Bursts

Apr 132019

A “photo burst”, on an iPhone or iPad, is a sequence of photos taken in rapid succession

Taking a burst of photos can improve your chances of getting a good picture in situations when things are moving quickly and you can’t go back and do it again if you miss it the first time.

The way that you take a burst of photos on an iPhone is simple in that all you have to do is keep your finger on the “shutter button” (the white circle in the Camera app) for a few seconds. The camera will then take a rapid sequence of pictures for as long as you press the button. Incidentally, you don’t have to press the “shutter button” to take pictures. Clicking on either the “volume up” or “volume down” button while the camera app is open will also take pictures.

If you now open the Photos app and go to the picture that is a “Burst”, you will see some text near the top left of the screen saying, for example, “Burst (22 photos)”. Note that if you tap on the image (so that all the surrounding text and icons disappear), this text also disappears and you can not tell that you are not looking at a normal, single, image. If this happens, just tap on the photo to bring the icons and options back.

When you are looking at a burst, there is a new option below the image that says “Select…” If you tap on this, you can then scroll (left to right and vice versa) through each separate image in the burst to see which one(s) you would like to keep as separate images. For some odd reason, the first image you see will be part way through the sequence so you have to scroll leftwards to get to the beginning. As you scroll through, just tap on each image to be kept and a tick will appear in the bottom righthand corner of each one. When finished selecting, click on “Done” (at top right).

The first time you select images from a particular burst, pressing “Done” will bring up the option to “Keep Everything” or “Keep Only 5 Favourites” (or however many you ticked). If you choose to “Keep Everything” then you will keep the “burst” (ie all the images in the burst presented as a single “burst image”) plus you will keep separate images of the ticked items in the burst. If you choose to keep only the favourites (ticked items) then the burst will be deleted. This is obviously good for saving space on your device, but the burst will now have gone to data heaven and can’t be accessed again.

If you want to revisit the burst and save further images from it, just display the burst in the photos app again, click on “Select” and choose further images to save separately. This time, however, when you click “Done” you will not be presented with the option to “Keep Everything”. This time the burst will be automatically saved and the images that you have just chosen will also be saved (as separate images).

Not re-presenting the option to “Keep Everything” is one thing that confused me when first looking at bursts. Another is that I expected the option “Keep Everything” to mean that each single image in the burst would be automatically saved as a separate image. That’s not what it means. Rather, it means “keep the burst plus any ticked images”. To keep each image in the burst separate from the burst, just select each image in the burst and click “Done”.

The illustration below shows every fourth image in a burst. No doubt, most people could have found a more interesting subject.

Having now got to grips with how “burst” works, all you need to do now is remember to use it in those few seconds that it would be useful!

Remember the camera on your phone

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Apr 132013

This week’s blog is about encouraging old dogs to learn new tricks

My father enjoyed photography. From the late 1940’s to the mid 1960’s he developed and printed his own black and white photographs. I have clear and fond memories of “helping” him in his darkroom (or “bathroom with the window blacked out” as other people might call it). The prints he produced were usually tiny by today’s standards. Often no more than about 5cm X 3cm. I think this was because photographic paper would have been an expensive luxury in the post-war years when his photography habits developed (ha-ha).

Although it’s illegible here, this receipt is perfectly legible in its saved format for viewing on-screen or printing.

When I bought my own first camera (with money from my paper round) I also had to pay for my printing and developing costs. But I don’t think it would just have been schoolboys who found the hobby was still quite an expensive business in the mid to late 1960’s. As well as the cost, though, there was always the inevitable delay between taking a picture and seeing the results (even if you had your own darkroom).

All of this has changed enormously with the advent of digital photography and, especially, cameras built into mobile phones. I suspect that young people who have grown up with this technology automatically take photos of things that wouldn’t occur to older people, for whom photography was an expensive business that usually only happened on “special” occasions, and that required a bit of a rigmarole to produce visible results.

The photo is straight, the writing isn’t.

I may be wrong about this, but I think that older people may be more rigid in thinking about when it is appropriate and useful to take a picture. And I also think that the mental process that triggers the impulse to take a picture may often be started by the social situation. So, an older person would deliberately take a camera to a wedding or a christening and would expect to take pictures of happy couples and bonny babies. But would that same older person spontaneously think to take a picture with their smartphone of something that could be useful in the future but which may be more prosaic – a receipt for a taxi fare, for instance?

As you have probably gathered, I definitely include myself in the category of “older people” – as far as photography habits are concerned, anyway! I’ve been trying hard to create new habits of using the camera on my iPhone and I’m finding that, slowly, those habits are beginning to form. Here are some situations where it’s useful to remember you’ve got a camera – with no processing costs or hassle:

I’ve got a whiteboard in my kitchen and I jot down shopping items as they occur to me. Some brain cells must have jumped into action one day when I realised that I can simply photograph the list on the board before tripping off to Sainsbury (or Waitrose – we’re now getting posher in Clapham).
When shopping, I take pictures of items I’m shortlisting. This helps if I want to think about the choices later.
Also when shopping, I have taken pictures of labels with measurements (on storage items, for instance) to check later whether the item will fit.
On the underground, I take pictures of event posters (forthcoming exhibitions, for instance) so that I can remember to follow them up.
I have sporadically photographed items for insurance purposes (all of the toys I carry in my work bag, for instance, such as netbook, iPad, computer glasses, and so on). You can imagine other insurance situations – such as snapping the damage for which you are making a claim.

I’m also getting better at remembering business and computer applications – for instance:

Photographing licence numbers, usernames and passwords (yes, I know, these must be transcribed later and the photos deleted).
Taking a picture of the current wiring situation at the back of a computer so that I know what goes where before unplugging everything.
Just last week, a computer client snapped her computer screen and emailed the result to me because she wanted advice about what she could see on-screen. Great. Simple and effective. As I’ve mentioned before (see “Snipping and Snapping”), this is particularly useful if you’re seeing an error message that needs to be followed up and you want to record exactly what it looked like (and exactly what it said) before doing anything that could risk removing it from the screen.
Possibly the most useful occasion is to use a smartphone camera on all those occasions when you need to scan a piece of paper just to have a record on the computer, but when you don’t want to go through all the hassle of scanning. A smartphone camera may not give you the quality of a scan, but the result will be legible and will still provide that permanent record. I was discussing this with a client just yesterday. He already has a business-quality printer and was thinking that he needed a business-quality scanning solution to permanently store all the receipts he collects on his numerous global trips. His eyes lit up when I suggested trying the camera on his phone. He’s going to give it a whirl. If it works for him it will be a free and effective solution.

And then, of course, there are those spontaneous moments when you see something you just want to record and you remember you’ve got a camera with you! Here’s a couple I prepared earlier:

Billy Fury Way – snapped in West Hampstead just last week. I know, I’m showing my age just by remembering him.

Not a very good photograph, but it gives me a smile to remember the day I saw Excalibur arising from Long Pond,Clapham Common.

Basic Techniques In Photo Editing

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Dec 222012

My computer clients often ask me how to get started in editing their digital photos

There are many photo editing programs available, ranging from excellent free programs to Adobe Photoshop costing many hundreds of pounds. In this blog I am not interested in specific programs. What I would like to do instead is give you an idea of some of the basic functions that you will find in all image editing programs (even Mac programs!) and which, between them, can go a long way to improve your photos. Editing photos can be a satisfying and creative way to spend time. It’s not a “task” to be fitted in between checking your email and updating the family budget spreadsheet. Personally, I get more satisfaction from editing photos than from taking them. I would recommend thinking of time set aside to edit photos as being “quality time”: time spent doing something that can give real satisfaction.

So, let us look at a few of the techniques available in all the different software packages. If you apply each of these techniques (where relevant, of course) to each photo you wish to improve, then you will almost certainly be surprised and pleased by the results. I am going to list these in the order that I use them when editing my own photos.

1) Straightening the picture

You can turn the photo so as to straighten it. Since this process means that some parts of the photo will be lost, I do this first as there’s no point in creating a satisfying picture using other techniques, only to have the image look different after part of it has been lost in the straightening process.

The lopsided horizon spoils this image, taken on the North Kent coast

With the horizon straightened, the attention is drawn instead to the beach huts. They look as if they are staring out to sea.

2) Cropping the picture

Cropping an image consists of cutting away parts that are not wanted. I don’t mean removing details from WITHIN the image. Cropping is like taking a pair of scissors and just cutting off as much of the edge of any of the four sides as desired. This is a much more creative process than it might, at first, seem. The entire balance, focus, and mood of a picture can be greatly changed by the way that the image is cropped. I crop the image early on as there’s no point in doing any of the later detailed work on parts of the image that are going to be removed.

With large areas of boring background, this image is not very interesting

After cropping, the reflections in the instruments make a far better focus for the image.

3) Adjusting the levels

An image, as taken, may have no areas that are very light and/or no areas that are very dark. This can make an image look “muddy”. Adjusting the levels means making the darker areas nearer to (or completely) black and making the lighter areas nearer to (or completely) white. This is a far better way to increase the difference between the lighter and darker areas than adjusting the contrast (although this can also be done. I tend to gently “tweak” the contrast at the end of the editing process just to give an image a bit more punch).

With the levels unadjusted, the best place for this image is the recycle bin.

This image has been rescued by adjusting the levels (OK, I agree, it’s still boring)

4) Removing red-eye

Red-eye is the phenomenon of light from the flash of your camera bouncing off the back of the subject’s eyeball, resulting in red eyes in the photograph. Most image editing programs have options that can automatically detect and remove red-eye. It can also be done manually.

Red-eye can completely ruin a portrait

Removing the red-eye can make all the difference

5) Cloning

After applying the above techniques to more-or-less all photos, the next thing it’s definitely worth getting to grips with is the process of “cloning”. This is where the real magic of photo editing starts. Cloning is the process whereby you select a piece of the image and you copy that part of the image to somewhere else on the image. This, effectively, makes what had previously been on the copied area disappear. You can see it in the illustrations of the “skull sculpture” ( “Very Hungry God” (2006) by Sudobh Gupta as displayed in the Frieze Art Fair in Regent’s Park). The first image shows the actual reality that I photographed. The second has been “doctored” by me using the cloning tool to remove the legs of the sculpture by replacing them with copies of nearby content (ie greenery). The result is quite spooky: the skull (spooky in itself) seems to float in mid-air.

The “real” image with the legs (as the sculptor intended!)

Parts of the background greenery have been cloned over the legs, making them disappear

This is just a taster of what can be done in photo editing. I’ve lost track of the number of my clients who have said “I must get round to doing something with my photos”. Well, these steps are some of the basic and easy ones, but be warned – it’s surprising how much time can just disappear as you become totally absorbed in the process. And apart from enjoying the process, the results are definitely worth it. You can make a real difference to how your photographs look and derive real satisfaction from doing it.

I would be delighted to provide training to help you down the road of getting some real fun and satisfaction from your computer through photo editing

QR Codes

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Apr 142012

QR Codes are not to be confused with Space Invaders.

This is a Space Invader:

This is a QR Code:

What they have in common is that they’ve both been popping up in public places for the last couple of years. I think I used to be a bit confused about what they are and whether they are somehow related to each other. They are not. The Space Invaders are graffiti, composed of ceramic tesserae in patterns recalling the old Pacman and Space Invaders computer games of 30-odd years ago. These graffiti pop up unexpectedly all over London and always give me the same smile as spotting a new Banksy.

QR Codes, on the other hand, are like barcodes. They contain information that can be instantly “read” and transferred to the device that reads them. Barcodes in supermarkets are usually read by laser beams. QR Codes are read by the camera on a smartphone or tablet computer (or even a laptop computer if you feel like opening it up in the street and pointing the camera at shop windows, posters, etcetera). The software that captures the image extracts the data from it and sends it on to somewhere else (such as creating a new contact in an address book or automatically completing a website address in a browser).

What’s the point? They make capturing information for later use very simple. How often have you wanted to record something that you see (such as a phone number) for later use, but haven’t had a pen or haven’t thought it worth stopping to dig out out a pencil and paper, etc? This, of course, is one of the great uses of the camera on a mobile phone. Just take a picture of something you want to turn your attention to later and let the image on your phone serve as a visual reminder. You do have to be a little careful when doing this sometimes. Believe it or not, I was asked to leave PC World in Tottenham Court Road a few months ago for photographing a laptop I was shortlisting. My claim to fame as a computer consultant – ejected from PC World. Oh, the shame of it.

Anyway, QR Codes take these “reminder snapshots” a stage further by extracting text embedded in the image and passing that text straight to where you need it – the address bar of a browser, for instance, or your address book.

I suppose that there’s a chance that QR Codes (Quick Response Codes) may not become universally used. Passing contact details between mobile phones via bluetooth never caught on widely. My guess, though, is that they are here to stay because they’re so easy. You can definitely pass contact details between mobile phones more quickly by QR Code than by manually inputting the data (and there’s no chance of typos). Nevertheless, I can imagine half the people reading this blog echoing Shirley Conran’s opinion that “Life’s too short to stuff a mushroom”. I recommend that if you use a smartphone and you know how to install an app then QR Codes are well worth spending just a few minutes on. Who knows, they may save you enough time in the future that you can afford to spend some of it stuffing mushrooms.

And if you do decide that you’re firmly in the Shirley Conran camp, at least you now know what those strange square boxes are all about.

Pacman and paint roller graffiti spotted in Rathbone Place, W1, on 13/04/12

PS: I’ve just had a thought. How would PC World have reacted to my phone’s camera if I had been capturing a QR Code and not taking a picture of a potential purchase? Hmm, I think I’ll stick to my usual purchasing policy regarding PC World – only do it when I know they are the cheapest, when I don’t have to ask them anything at all, and when there’s very very little chance of having to return it.

Sizing Digital Images

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Feb 112012

What do we mean by the size of a digital image?

In the last week one computer client asked me why I don’t blog more on digital photography and someone else asked me to clarify how you change the size of image files. This kind of technical advice is probably better imparted in a 1:1 computer training session, but let’s see if I can help at least two clients in one go.

On this subject, it’s easy to conflate two different things and get thoroughly confused. These two things are:

The amount of information there is in the digital image and, therefore, the amount of space it takes to store it.
The physical, measurable size of the image if we print it or view it onscreen.

1) Information in an Image

As explained in a previous blog on digital images – a bitmap digital image (the more common type of digital image) can be thought of as a grid of tiny squares in which each tiny square is a single colour. A single square (known as a “pixel”, meaning “picture element”) can only be a single colour. So, if you have an image that is broken down into a grid of 1000 squares across and 1500 squares down then you have a picture comprised of 1,500,000 pixels. That figure is one way of describing the size of the image. Another way of saying this would be “One and a half million pixels” or, as you will see written on the point of sale literature for cameras, “1.5 mega pixels”.

The next aspect is to consider how much information there is in a single pixel. If the image is a “greyscale” image, containing only black, white and varying shades of grey in between, then each pixel is likely to be assigned one of 256 different shades of grey (including the black and white at either end of the scale). If we wish to record/describe the colour of any pixel then we can assign a number from 1-256 (representing each colour from white to black) to each pixel.

So, the total size of the image in terms of the amount of space it takes up on your computer or camera is the number of pixels (1,500,000) multiplied by the amount of space required to define the colour of each pixel. As it happens, it takes 1byte to define any of 256 colours so our image is going to be about 1.5mb in size. If this is a colour image in which each pixel can be a combination of any of 256 shades of red, green, and blue (known as an 8-bit RGB image) then we will need 3 bytes to define the colour of each pixel so the total size of the image will be 4.5mb.

This is a slight simplification of the actual size of the file, but the reasoning is sound. The file is likely to be slightly larger in practice because it will also contain other information known as “meta data” that doesn’t form part of the image itself (eg information about when the image was taken, the settings of the camera etc). Going in the other direction, though, if the image is a digital photograph then it’s highly likely that it will be in a “jpg” format – in which case the file will be “compressed”, thereby making it smaller (but we needn’t go into that here).

So, if you wish to email an image or upload it to a website and know that there is an upper limit to the size of the image, then it is the factors above that you need to consider – see this blog on emailing large attachments. If you’ve prepared your image in an editing program such as Photoshop and the resulting file size is too big then you need to do one or more of the following:

Crop the image (chop bits off it)
Reduce the “colour depth” (number of different colours available for each pixel)
Increase the compression at the expense of quality (if it’s a jpg, for instance)
Change the number of pixels into which the image is divided.

It is the last of these options that we are going to consider here. Look at the dialog box in Photoshop for changing the number of pixels in an image. Note that we haven’t yet mentioned “dpi” and we don’t need to! DPI has nothing to do with the size of the image as it sits on your computer or flies through cyberspace. Just change the number of pixels in the dialog box (under “Pixel Dimensions”) and the size of the image is immediately changed. And note that since we are working in two dimensions, halving the size of each dimension (height and width) would quarter the size of the resulting file. The easiest way of reducing the size of the file is to reduce the number of pixels it contains.

2) Displaying an Image

When displaying an image on a computer screen, or printing on a deskjet or laser printer, the image is made up of “dots” or “pixels” as created by the computer or printer. The density of these dots is what defines the size of the physical result.

So, if we have an image of 1000 X 1500 pixels and print it at a density of 200 dots per inch (dpi) then the printed image will measure 5 inches by 7.5 inches.

If we increase the number of dots per inch we will be packing the pixels closer together. This means that the image will (a) appear sharper (within limits) and (b) be smaller when it is printed.

So, if we print the same image at 300dpi then it will measure 3.3 X 5 inches when printed.

The crucial thing to appreciate is that we haven’t changed the size of the image itself. It’s still 1000 X 1500 pixels and it will still take up the same space on the computer. The decision to print it at 200dpi or 150dpi or 300dpi is separate from the size of the image itself. In practice, whatever your printer tells you it is capable of producing, you are unlikely to see any difference in printed quality if you raise the density (or “resolution”) higher than 300dpi but if you drop it to less than 150dpi you are likely to see the quality drop.

I’m not suggesting that there is no connection between image size and printing resolution. Clearly, whatever the resolution, the printed image will be larger if there are more pixels to print and if there aren’t enough pixels available then printing in lower resolution to get a larger print will reduce the quality of the printed result to unacceptable levels.

The important point I’m trying to make here, though, is that “dpi” has nothing to do with file size. Changing the “dpi” will not change the size of your file.

See this Wikipedia page on dpi for more detail on this topic.

You may also like to refer to these previous blog posts:

File Sizes
File Sizes – 2
Checking File Sizes

Treepad

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Oct 082011

A lot of business users and home computer users automatically turn to Microsoft Word every time they want to create text that needs to be saved. Word is a great fully-featured “word processing package” but using it often seems like using a sledge-hammer to crack a walnut, and it doesn’t necessarily offer a good solution in terms of organising snippets of information and finding them again in a hurry. Indeed, a lot of people would argue that Word has now become too clever and complicated for its own good, confusing average users with a plethora of options while not answering the real-world needs of data storage and retrieval.

Think, for example, of wanting to record notes about household things such as car maintenance records, or recipes, or anything else where you want to record information that you might just need to find again in the future. It seems to me that the trick is to make it as easy as possible to do the recording while, at the same time, making it as easy as possible to find something in, say, a year’s time.

Let’s take this a bit further by adding the possibility of including images (including screen captures), links to web pages, and links to files on your own computer. What we are beginning to see now is not just a program for recording text but an entire “information management system”.

Microsoft does have its own program for this kind of need. It’s called OneNote and it’s included in all Microsoft Office packages. However, in all the years that I’ve been providing computer support in London I have never heard a single client mention it. I’ve been testing it for myself for the last three months or so. If I decide it’s worth using I’ll write a blog post on it, but I have to say that so far I’m finding it a bit irritating and possibly resource-hungry. On the other hand, it does seem quite powerful and useful.

In the meantime, the program I use for this kind of thing is one called “Treepad”. Indeed, I write these blog posts using Treepad and then copy and paste them onto my website. The reasons for using Treepad in this context are:

I can concentrate on creating the text without worrying about formatting etc.
I can easily drop images into the text that I might want to include in the blog post.

I also use Treepad for all kinds of computer technical notes that I may never need again or that I might just need one day. I have found that the really important thing is that the effort of writing down and saving information like this is only repaid if it’s easy to find it again. That also means that it has to be easy to do the recording. Treepad is excellent in these respects.

Treepad - showing the tree and part of an article

Figure 1 - Treepad - showing the tree structure on the left and part of an article (the contents of a node) on the right

Treepad is basically a text manager that allows you to organise content in a “tree structure”. On the left of the screen is the structure, and on the right is the content of the particular “node” that is currently selected. Nodes can be “nested” inside nodes in much the same way that Windows organises folders within folders (see Figure 1). By the by, you can see from the top of Figure 1 that I keep my Treepad files in my Dropbox folder so that they are always available on all my computers – see my blog about Dropbox.

But it is not only text that can entered into a node. We can also paste images, hyperlinks to programs or data files on the same computer, hyperlinks to websites, and links to other nodes in the same Treepad data file. It’s very easy to use and it’s powerful.

The only major gripe that I have with Treepad is that there is no inbuilt “tagging”. By that, I mean the ability to define each node as belonging to one or several user-defined “definitions” or “groups”. For instance, I might want to tag the content of nodes with “computer support London” or “silver surfer pc training” or “one-to-one computer training” or “blog ideas” so that all nodes with one or more specific tags can be selected easily. This is not absolutely critical, though, as there is a search routine, so I try to remember to add the words that I would like to treat as tags to the top line of the content of nodes. If I then search for a specific word it will list all nodes that include that word.

Figure 2 - Treepad Search Results

Figure 2 shows the results of searching my Treepad file for “AVG”:

I can then click on any selected node to see it in its entirety.

Treepad is available in several versions. There is a free version so it costs nothing except a bit of time to give it a try. If you are the sort of person who is forever mislaying bits of information that you think should be easily accessible on your computer then it could pay you to have a look at it. I’ve been using the “Business” version for several years.

I started looking at Microsoft’s OneNote because it appears to be a more sophisticated program (you can scan documents directly into OneNote for instance), but I find its text handling a bit, shall we say, idiosyncratic (ie annoying) so I don’t know yet whether I would recommend it. Treepad is beginning to look a bit long in the tooth but it’s easy to use and repays the minimal effort required to use it.

I’m going to have a look at how good Treepad might be as a password manager program as I know that most of my IT clients do not have a simple, effective, consistent way of storing these and could do with a bit of well-aimed computer advice on the subject. Watch this space….

Digital Image Formats (2)

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Jul 092011

The Compromise of the Jpeg Format

As mentioned in the digital formats blog last week, each time you edit and save a jpeg file a process takes place that aims to reduce the size of the resulting file. This entails making some approximations about the content (the colour) of some pixels. Repeatedly saving a jpeg file will, therefore, degrade its quality.

Whenever you save a jpeg file, most programs will offer you a choice as to the trade-off you would like to make between the size and the quality of the file you are going to create. In the illustration here, I am choosing to save the best quality file, but it will be the largest. I could change my choice by moving the slider, entering a different number, or choosing a quality other than “maximum”. This illustration is from the Photoshop program. Different programs offer variations on this, but the result is always that you are making a choice between quality and size of file.

Note: merely viewing your jpegs (as opposed to editing and then saving them) will NOT degrade the image. And neither will time! Real, hard copy photographs do degenerate over time as chemical processes take their toll. Digital images on your computer will not suffer this fate.

Images as Email Attachments

If you are intending to send an image file as an attachment to an email then size matters. An image of acceptable quality saved as a jpeg could be 200kb or smaller, whereas the tif equivalent could be 20mb. The former would be perfectly acceptable as an email attachment, whereas the latter may not be delivered. As far as emailing jpegs is concerned, you can almost always save the jpeg at its highest quality and still have a file that will comfortably go through the email system. You can see in the first illustration that the file I am saving here would be 153.0k. This would be perfectly acceptable as an email attachment.

Quick reminder on file sizes: there are approx 1000kb in 1mb (one thousand kilobytes in a megabyte). An email attachment can be 5mb without causing problems and some email systems can handle attachments up to 20mb. Therefore, any file size that is expressed in kb (and is less than 5000kb) is less than 5mb. Therefore, any file size expressed in kb (provided that it is less than 5000kb) will be ok to send by email.

The Best of Both Worlds

If you only intend to edit a photograph once or twice then it’s probably OK (quality-wise) to save it each time as a jpeg. The quality will remain acceptable and it won’t cause problems by being too large. If, on the other hand, you are going to do a lot of editing, spread over several sessions, then it is worth getting to grips with how you can save an image in a “lossless” format such as tif or bmp, so that it doesn’t degrade each time you save it. When you have finished editing it you can save the final version as a jpeg so that you then get the benefit of compressing it without all the intervening stages of degradation. If you do this, by the way, you will finish by having a file in each of the jpeg format and the “lossless” format.

Whatever program you are using to edit your pictures, the way to save an image file in a different format is to find the command to “save as” (as opposed to the “save” command) and then look for an option to allow you to change the format. This illustration is from Photoshop:

In this instance, clicking on the triangle to the right of the “Format:” line offers many options for saving the file in a different format, including tif. When you have finished all the editing and want to create a final, smaller, jpeg file then just issue the “save as” command again and choose jpeg as the final format.

Zipping Image Files

Files can usually be compressed into smaller sizes by putting them into zip files (or other compressed formats such as rar). These can then be sent more easily through the email system. Zipping also has the advantage that only one file is sent, so it is easier to handle than trying to attach, say, 20 photograph files. The recipient then “unzips” the file back into its original components.

There is no reason why you cannot put jpeg files into zip files, but you won’t save much space. The jpeg has already been optimised, so the process of “zipping” it won’t squash it much more – if at all. Zipping “lossless” files (such as tif files) will reduce the overall size considerably and won’t compromise the quality of the image.

Having said all that, there are now many alternatives for showing other people your digital photographs that don’t involve trying to send them through the email system, so if you regularly send lots of images it’s worth considering them. These alternatives include posting images on your social media page (eg Facebook), storing them online on Microsoft’s Skydrive system or Kodak’s online photograph album system, or even creating your own photo website.

There are lots of other aspects of digital images that we could look at, so I think we will be returning to this subject before very long.

In the meantime, you can find more information on jpegs here.

Digital Image Formats

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Jul 022011

There are two main ways that a digital file can store information about an image:

Vector images are made up of independent objects (eg circles, arcs, squares). Each of these objects is defined in terms of mathematical relationships and instructions as to how to create it. A square, for example, is defined by where it is placed on the image, the length of a side in relation to the size of the entire image, the thickness and colour of the defining edges and so forth. This sounds complicated when explained in words but, in fact, the size of images made up of vector shapes is typically much smaller than an equivalent bitmap file (see below). This is because it is not the image itself that is stored – just the instructions necessary to re-create it.

The other main feature of a vector graphic (or image) is that it is “resolution-independent”. If you print a vector image the size of a postage stamp, its sharpness will be the same as if you printed it to fill a whole A4 page. Vector graphics are used in situations such as computer-aided design where images are made up of individually created elements and where sharpness and clarity at large sizes are important. Unfortunately, vector graphics won’t work for us in a lot of situations because the image (eg a photograph) can not easily be broken down into objects that can be defined geometrically and mathematically.

The image of the zombie was created as a vector image (source).

Bitmaps or raster images are the more familiar format of graphics file for most people. In a bitmap file the image is composed of thousands or millions of individually coloured rectangles or dots, each of which is a single colour. These are called “pixels” (a contraction of “picture elements”). Pixels can be seen in the enlarged section of Tate Modern on the bitmap here.

There may be a choice of up to 16,777,216 colours available for each pixel. So, if you imagine a grid of 3000 pixels in one direction and 2000 pixels in the other, in which each pixel could be one of 16,777,216 colours, you are imagining what a bitmap image looks like. In this case, there would be 6 million pixels (3000 X 2000), so this is would be a “6 mega-pixel” image.

The problem with bitmap images is that they can be large – very very large – in terms of the space they take to store. It takes an awful lot of zeroes and ones to define 6,000,000 pixels when each pixel can be one of 16 million colours.

So, we can now say that the smaller, resolution-independent, type of image (ie the vector graphic) isn’t going to be any good to us if our images are, in fact, photographs (or anything else that can not be broken down into individual geometric “objects”). Therefore, we are usually going to be using bitmap (raster) images. This means that we are going to have to struggle with the play-off between the size of file that we create and the quality of the final image. It is largely to achieve the best compromise in this play-off that there exist several types of bitmap image:

Tif (or tiff) files tend to produce very large files because all of the information in each pixel is always retained (this is known as a “lossless” image type). This has advantages for quality but disadvantages for file size. It is often the preferred file format for people creating and editing images (including photographs) using photo editing software such as Photoshop.

Gif and png files (pronounced “gif” or “jif” and “pee en gee” respectively) are graphics formats producing very small files. They are mainly used for images on web pages. The small file size is achieved by reducing the number of different colours in the image to the minimum necessary to create that image at an acceptable quality.

Jpg or jpeg files (pronounced “jay peg”) are the most favoured for finished photographs. Almost all digital cameras will create jpg files (although a lot will also create other formats). The advantage is that the file is compressed to be smaller. The price to be paid for this is that some loss of information (which translates into picture quality) will occur. This probably won’t be too serious to begin with, but if you repeatedly edit and save a jpg image then the quality will continue to degrade.

Raw is a “lossless” format produced by many digital cameras. However, there are lots of flavors of raw images so you may need the software provided with the camera to handle them.

Bmp (bitmap) is a Windows specification of a lossless file. Bmp files can be large but they have the advantage that they can be handled by almost all programs that need to deal with image files . And, yes, we do now have two different uses of the word “bitmap”. It is used synonymously with “raster” (as distinct from vector images) and is also used as the name of a specific Windows file format.

Apart from the image itself, most image files can also carry other information (called “exif” information or “metadata”) that can be used and displayed by image-handling programs. This can include, for example, the camera type, exposure information, date and time of exposure, and – somewhat controversially – the exact geographical location where the photograph was taken (known as “geotagging“).

Although I’ve tried to keep this simple, we’ve only scratched the surface (ha-ha) of digital photography by just looking at how digital images are composed and the main formats of files. Next time, I will look in more detail at jpgs as these are initially the most commonly encountered files in digital photography.

Backups - 1

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Feb 042011

Notice the rather ominous “1” in the title. This is a subject that will take more than one blog post. So, today let’s just think about what “backups” mean and what they don’t mean.

When I asked Google to define “backup” the first offering was

an accumulation caused by clogging or a stoppage; “a traffic backup on the main street”; “he discovered a backup in the toilet”

You’ll be pleased to learn that that’s not what we mean here. A better definition (offered by Wikipaedia) …

In information technology, a backup or the process of backing up refers to making copies of data so that these additional copies may be used to restore the original after a data loss event. These additional copies are typically called “backups. …”

3.5 inch External Drive

So at its simplest, a backup is a copy that can be used to replace an original if it is lost, deleted, damaged. This backup can be a copy of a single file (eg an important spreadsheet) or many files. At its simplest, a backup can reside on the same drive as the original. The problem is that if the entire drive fails then the backup is also lost. Having a backup on an external drive is a much better idea but that still wouldn’t avail you if all your computer stuff was stolen or in the event of flood or fire. The only way to be really sure that the backup will be there if you need it is to keep a backup in a location physically separated from the original. In practice, I’ve only ever very rarely managed to train my clients to such a degree!

What a Backup Isn’t

A backup is not usually a copy of any of the myriad files that make up the Windows (or Mac) operating system, nor a copy of the files that make up the programs on your computer (eg Microsoft Office, Photoshop). If we suspect that something has gone wrong with Windows or with a program file then the best thing to do usually is to un-install the program and re-install it. In other words, we don’t just copy back files that are in a backup, but set in motion the process of removing the program completely in the proper way and then putting it back from scratch from the original master CD/DVD or downloaded file. The reason for this is that program files have to be copied and set up so that they work in the specific situation and in concert with the other programs and operating system. Copying files is not enough to achieve this so we don’t back up program files.

What Data should be backed up?

Your own stuff. The documents and spreadsheets and pictures and videos and all the other stuff that is YOURS and that you would not want to lose.

There are also other types of file that are not quite so easily imaginable as data but which you wouldn’t want to lose – eg that huge list of bookmarks (also known as favorites (sic)) that you build up in your web browser (Internet Explorer, Firefox, Chrome, Safari, Opera or whichever browser you use). That list of websites is nothing more than that – a list – but I’ve seen a lot of clients looking very deflated when they realise they’ve lost it.

2.5 inch External Drive

A hugely important part of backup data can be your email data. This is the email messages themselves, but can also be your contact information. If you only send, view, and receive your data through a web browser then your email data is not being stored on your own computer but on the computers of the service providers. This covers services such as Hotmail, Gmail, AOL mail, Yahoo, and others. This is known as webmail.

If, however, you access your email through a program on your computer (such as Windows Live Mail, Outlook, Outlook Express) then your email data is stored on your own computer. Your email provider may have a copy of your recent email history on their own computers (also known as mail servers) but it could be as little as the last seven days worth of data. Don’t rely on your mail servers as email data backups.

It’s also true that webmail can usually be accessed and downloaded with programs such as Outlook (as in the paragraph above), but we don’t need to split hairs about that now.

Having established an idea of what it is that we want to back up, let’s just finish this definition of what a backup is by considering some similar ideas:

An archive – in computer terms, an archive is just a backup but with one important difference. It is never over-written. Suppose you back up your data to an external hard drive. That drive is going to get full and you may wish to delete older backups to make room for newer ones. That means that you can’t always rely on your backups to tell you exactly what your accounts data (for instance) looked like on 23rd April 2009 (for instance). So, we often create archives in the knowledge that whatever happens we can see the data as it looked at a particular time in the past. Archives can be created in exactly the same way as a backup or by a different method. Often, for instance, archives are created on CDs or DVDs, whereas backups are made on external hard drives or USB pen drives (also known as thumb drives or memory sticks. A Memory Stick is actually a proprietary Sony device, so it is a misnomer to describe a generic USB pen drive as such).

An image – when we’re talking about backups an image is not a photograph. It’s a different meaning of the word and what it means is a complete, thorough, 100%, copy of EVERYTHING that is on your hard drive (or a sub-division of a hard drive such as a partition). An image can only be created using special software but it does seem to contradict what I said earlier about not being able to back up programs because a complete total image of your drive can actually be used to restore your computer to exactly what it looked like at the time the image was made – operating system, programs, data, the whole lot. But it’s not the panacea it sounds like because restoring an image could result in losing all the changes to the data that happened after the image was created.

Pen Drive

A clone – similar to an image, a clone is the entire copying of one drive (or partition) to another similar drive so that it can be swapped with the original in case of disaster. The problem with images and clones is that they can take a while to create, you can only be completely certain they’ve worked by installing them, and they don’t change as data is added or changed.

That’s an introduction to backups. The next blog on this subject will look at the actual creating of backups in more detail.

One final word: I implore you to keep your master program discs all in one place and know where that place is. I would include in that any data backups and archives on “loose” media such as CDs or DVDs. So many times in the past I have been summoned by a distraught client with an apparent disaster on their hands who needs programs (and maybe data) to be re-installed but they can’t find their discs. This is already a fraught situation. It just makes it more stressful and more expensive if the client can’t find the discs. This doesn’t need to get complicated: just put everything in the same box and know where that box is.

Great Free Software - Gadwin Print Screen

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Dec 032010

Do you ever wish the “PrtSc” (print screen) button would do what you want – eg

Print the whole contents of the screen to the printer
Print a part of the screen to the printer
Save part or all of the screen to an image file that you can use and refer to later

Gadwin PrintScreen does all of this. Amongst the options are:

Capturing the screen, the active window, or a user-defined rectangle
Sending the captured image to any or all of the clipboard, printer, email, or file
Choosing the file format of a captured image (gif, jpg, bmp, tif, png)

Set your options to begin with and then just use it. You don’t have to plough through the options each time you use it – just press PrtSc (or a different key combination if that’s what you’ve chosen to do). If you set it to load up when Windows starts, it’s always there – at a single keystroke.

A lot of the images in my blog are captured with Gadwin. It’s also excellent for capturing web pages as the results are exactly the same as you see on screen, whereas printing web pages can often lead to unpredictable results and pages and pages of guff spilling out of the printer.

It’s very handy for keeping a record of on-screen forms that you’ve just completed. I have a special folder that only contains “screen captures”. Gadwin is set to always save to that folder so I always know where I saved an image that I may want later. Periodically, I clear the folder of images I’m not likely to need again.

I have been using it for a year or two now and I just take it for granted. There is also a paid-for version (PrintScreen Professional – $21.95) that includes an image editor and annotation facility but I’ve never needed this.