This
scenario is played out every day in offices around the world. You get a hi-res
image sent to you and have to use it in an intranet feature. But
how do you get the best out of it and what are the tricks of the trade? Steve
Nichols takes a look.
The
problem with hi-res images straight out of a camera is that they are just too
big for the net. Typically, you need something about 250 – 350pixels wide, not
the 3000-odd pixels that the average Nikon or Canon DSLR creates.
So
what do you do? The first step is to make sure that you have a decent imaging
program. While PCs come with PhotoEditor, in my opinion it is pretty useless at
creating good images for the web. Far better is Adobe Photoshop Elements, which
has about 80% of the functionality of full-blown Photoshop, but only costs
around £65 for Mac
or PC.
The
main difference between Photoshop and Photoshop Elements is that the lesser
version can’t convert the colour model from RGB to CMYK. That is, it can’t
prepare images for print. But for web use you don’t need that anyway.
So
having installed Photoshop Elements what do we do?
First,
open your hi-res image and use the cropping tool to crop what it is you want out
of the image. Most people include way too much clutter around the images, which
must be cropped tightly to maintain impact when used small.
Once
you have cropped the image go to “Enhance >> Brightness and Contrast
>> Levels”
This
gives you a graphical illustration of the tones in the photograph, from the
blackest black on the left to pure white on the right. A typical well-exposed
image has a full range of tones, but you can see that our image is shifted to
the left – the dark tones don’t come all the way over to the right.
But
this is easily fixed – just click and drag the right-hand triangle under the
graph and move it down to where the graph appears to finish. You now have a
good spread of tones and the image is much brighter, but still not quite right.
But
if we move the central triangle towards the left too, the image improves even
more. The central triangle defines what is going to be the mid tone of the
image.
The
new graph may look a mess as we have effectively reduced the overall number of
tones in the image, but as it is only for the net this is fine.
This
is something you might need to practice with, but the levels are a powerful
tool and much better than just using the Brightness and Contrast controls.
Now
we need to reduce the size of the image. Go to “Image >> Resize>>
Image Size” and change the width to 250pixels or whatever size you use. Make
sure you have “Constrain Proportions” and “Resample Image” ticked.
The
image is now at the right size for the net – zoom in until the image says it is
at 100%. This is now the size it will appear in a web browser.
There
is now one final thing to do. Images that have been downsized always look
slightly fuzzy. We can sharpen them by going to “Filter >>Sharpen
>> Unsharp Mask”.
Set
the Radius to 1.5 pixels and the Threshold to 5 levels. Now set the amount to
somewhere around 50 – 100. You can see the effect you are having by clicking on
and off the “Preview” option.
Don’t
overdo the sharpening. Once you are happy click OK.
Now
all you have to do is go to “Save for web” and select JPEG, and a “Quality”
level of “High” (about 60%). This will depend upon the image, but if in doubt
make the image quality better rather than worse.
Now
save your image. The end result will be a file of about 20K, which will load
very quickly on a webpage or intranet site.
If
you want to learn more about using Photoshop I can recommend a series of videos
called “Learn Photoshop Now
– in just two hours”. Steve Nichols runs
InfoTech Communications (www.infotechcomms.co.uk) and is editor of this
web site. InfoTech specialises in online communications and Steve has acted as
consultant and trainer for many blue-chip companies including Aviva, AWG,
Shell, BT, Standard Life, HBOS, BNFL, Accenture and Australia New Zealand Bank.
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