Please notice I have done NO sharpening yet. This should be the LAST thing you do to your image for web presentation.
The first thing I will do is change the depth of the image from 16bit to 8bit (image > Mode > 8bits/channel). Then I will ensure the colour profile is set to sRGB IEC61966-2.1 (Edit > Convert to profile > Destination Source). You will notice in the diagram below that my Source space is already sRGB. That is because I opted to output that colour profile during my RAW conversion stage. It's possible that not all RAW conversion software will let you do that, so I thought I'd include it here as it's important for web images.
The next thing I do is to resize the image for the web. Most photo sites have maximum posting limits. NPN where I post use 720pixels on the longest side, so that is what I will be using for this exercise. IN CS3 i will use the Image Size option (Image > Image size)
I set the Resolution to 72 pixels/inch and then set the pixel dimension longest side to 720px. By checking the box "Constrain proportions, the image will resize the shortest side without elongating or squashing the image. To resample the image, I use bicubic and this has been recommended by others (although I haven't personally tested the differences).
The image is pretty much ready now apart from the sharpening, which I stress again, should be the last in the process, so if there are any more adjustments you think are needed, make them now! Also if you want to add borders, signatures and copyright symbols, add a layer and do these at this point.
Sharpening for the web
Now, the sharpening.... I select the areas that I want to sharpen by using the 'magic wand tool' and basically any tool that allows me to select the areas I want. Sometimes it's hard to use the 'magic wand' due to similar tonal areas, so I will add a layer mask and paint the selection using the 'pen tool'. The reason I use a selection rather than sharpen the whole image is most occasions, everything will not need sharpening. Skies, soft backgrounds etc will suffer unnecessary processing signs such as artifacts and halos. A good tip is to get the selection as precise as you can and then use the Contract option to contract your selection slightly to avoid sharpening halos. I would contract my selection by 2 pixels. Once I have the completed area selected, I apply my sharpening.
I then select 'Unsharp mask', sounds weird I know,as I want to sharpen the image, not unsharpen it! (Filter > Sharpen > Unsharp mask). The settings I use in the sharpening dialogue box means that I can progressively sharpen the image rather than whack it full tilt and then going back and adjusting it. The settings I use are 100, 0.2, 0.
I select Ok and then go to Fade (Edit > Fade Unsharp mask...) and select the luminosity setting and select Ok. This apparently reduces artifacts as it reduces the luminosity of the sharpened pixels, which apparently is a good thing! I did say I was poor technically in Photoshop!
I then run another dose of sharpening at the same settings and again Fade the luminosity process after each sharpening dose. I generally apply the sharpening and fade 5 times, or until the image starts to look a bit crunchy. The good thing about Photoshop is the History facility in that if I think it looks over sharpened, I can go back and delete the last sharpening dose.
Some images will take more sharpening than others but I would say 90% of the time I do the 5 runs, so I have setup an 'action' in Photoshop to do this as it's quite laborious doing the sharpen and fade every time.
Well that's it except for saving for web. By using the Save for Web facility, the Exif data (image technical details) is removed meaning your image consists of as much image colour data as opposed to a load of technical detail which counts towards your maximum image posting size limit. (a small detail, but makes sense to get as much detail as you can in your web image as opposed to some embedded unseen data).
Select Save for Web (File > Save for Web and Devices). The diagram below shows the settings I use
The red line shows that I can choose to Optimise to File size. Certain photo forums etc have rules for posting and generally it's a longest side size and maximum file size. You can choose here to input the largest size you can post and the software will restructure the data automatically. The 'quality' will generally decrease, but anything above 70% is acceptable. Any lower quality than that will exhibit compression problems.
And that's it for this method. All of my images in this web site have used this method, so make up your own mind if it's any good or not. I will cover some other methods which I find applicable and helpful in some images in the next sharpening articles