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This section covers typical methods for saving
graphic files, so that the retouching you've slaved over will last forever.
Given that you've spent time retouching and color-correcting graphic
files in Photoshop, you should not simply print your creation. Save it as well in the best possible condition,
which means in a format that will not cause a loss of image quality, while also embedding its proper color
space within it in the form of an ICC Profile.
First of all, let's explain that by loss of image quality, we
do not mean that it will fade like regular photographs. These are digital graphics, after all. If you make
a mistake in choosing a file format in which to save an image, it will end up as a low-detail image. The file
format that does this is called JPEG.
JPEG uses the properties of the human eye, which is relatively
insensitive to color despite being sensitive to light, to break up an image into blocks and group colors within
each block together. By compressing the data in this way, JPEG achieves its greatest advantage, to wit, making
files smaller. At the same time, however, images compressed with JPEG also lose detail equal to the amount
of data reorganization that has taken place.
Changing the level of compression when the file is saved can result in files that are highly compressed and, thus,
very small at the expense of low image quality. Conversely, JPEG files can be saved with low compression and, thus, high
image quality. This last choice, however, is only a question of degree, not all: images saved as JPEGs will inevitably experience
loss of image quality.
JPEG is also used to save images taken with digital cameras, the
purpose being to reduce file size as much as possible to enable taking lots of pictures at a time. If you look
at a detailed enlargement of what appears at first glance to be a clean image, you can see the blurriness,
or block noise, that JPEG introduces. If you open this image in Photoshop and save it as a JPEG again, it will
lose even more image quality. If these files are important to you, we recommend that you save them instead
in a lossless graphics format, such as TIFF or Photoshop's own PSD format, rather than JPEG.
One more thing to pay attention to when saving your graphics is
embedding ICC Profiles in them. When you open a graphic, and designate one ICC
Profile or another, that ICC Profile is preserved until you save the file. At that point, you can choose whether
to embed the profile in the file. As we have said repeatedly, an ICC Profile defines
the color space in which the graphic was created. Having an ICC Profile is what enables the correct reproduction
of that graphic's color in the first place. While it appears that many people do not get in the habit
of embedding ICC Profiles in their images because they find it to be too much trouble, we strongly recommend
that you get in the habit of embedding ICC Profiles in your images so that they will communicate their colors
properly.
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To save graphic files safely after you retouch
or color-correct them,we recommend saving them in either the Photoshop or TIFF
file formats. We also recommend checking the ICC Profile item, and designating that these profiles
be embedded into your graphic files.
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One more thing: if you have a graphic with layers in it, only the PSD or TIFF file format will enable you to preserve
those layers. While you can go ahead and save such graphics as JPEGs, for example, doing so will forcibly consolidate any
and all layers.
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Photo Retouch
