Now that we have seen, that pictures take damage from every conversion, we must conclude, that those pictures are to be kept in the largest possible color space as long time as possible.
It mostly is in the bright colors that sRGB is not as Adobe RGB. Lacking the blues, greens and yellows makes it difficult to get enough detail in these colors, which make the picture more vivid.
The first conversion is more or less one, that has to be done. The photographer has to correct the picture and this is normally don in RGB. But when the photographer uses professional equipment, the picture from the camera does not come in any jpeg format.
The “camera raw” format is far larger, containing more details, than the usual jpeg format. (Read about this here.) It is in this format that white balance and color corrections are made, and thus in the greatest possible amaount of details and colors.
The photographer sends the picture in the greatest possible RGB profile, which for practical reasons usually is Adobe RGB.
If you do not have any influence on the profile, you can “suffice” with sRGB, and if you get pictures from other sources, there may even be CMYK profiles. Conversion does not give any “enhancement, and there is great risk of detoriation.
If Adoe InDesing is set to convert pictures, when placing, you have a problem. If it is set to ask, when placing you can choose to convert, use the pictures own profiles or not using any.
It is best for CMYK pictures to let the picture keep its own profiles. This prevents the detoriation of clean colors into “muddy” ones. By using the pictures own profile, you ensure thatit is used as such later.
RGB pictures can be converted to InDesign’s working profile, which should be Adobe RGB. Through this you make sure all pictures are treated alike. Conversion from a smaller to a larger space usually is less destructive. Colors, which are not there are not added.
Then when the time comes to make a print file – PDF or PS – one has to make sure that the correct profile for the type of printing and the correct paper is chosen. The print shop should be able to supply this.
As a rule, when the plates are made, there has to be an adaption to the plate used, maybe to the press used, and to the specific paper. This adaption have to be precluded in the profile from the print shop.
So it is in making the print file that the final color space and the final print profile is chosen. These choices are important as ti is in this conversion – which usually is outside of your influence – that colors are adapted:
- A color space fitting for the print shops inks is chosen.
- A correct grid range – “translation” of the darkest and the lightest nuances – is chosen. This range is where you choose the type of paper or carton.
It may be, that in some cases there still has to be made some corrections for certain print processes or certain papers to avoid closing or burn outs (Closing: there is no raster in the color. Burn out: there is only the paper to be seen.) If the print shop has taken care of that in their profiles, than most pictures should correctly in that kind of printing.