How do I ensure that the colours printed more closely align with Relative Intent in Lightroom?

Question

I am in the process of preparing photos for a photobook to be printed with a volume commercial printer (zno.com). I have calibrated my screen, and have received ICC profiles for my printer, and am able to successfully soft proof against this in Lightroom.

The printer has told me that they only accept the photos in sRGB colour space.

When I softproof a photo (Simulate Paper and Ink is checked), it looks slightly under-saturated and lower exposure, lighter blacks when Intent is Perceptual. When I switch Intent to be Relative it seems to more closely match non-soft proofed copy, and I prefer the look.

The ICC profile itself (opened in Notepad) has a statement saying it is Perceptual.

I am aware that Lightroom printer module has an option to set intent, however there seems to be no such setting in the Export dialog.

Given my printer is a volume printer (photobooks) I would like to am unable to specify relative or perceptual intent to them.

Per the histograms, we can see that the blacks have been 'capped off' in the Perceptual image; if I play with exposure settings and set image to all-black then this is still the 'blackest' the image becomes. It suggests the ink will not go as black as the screen, and I can understand this. However what I do not understand is why the Relative intent shows blacker blacks.

Questions:

1. Am I correct in thinking that because the ICC profile states Perceptual then it is most likely that the Printer themselves uses Perceptual Intent for printing?
2. Am I able to convert the colour space mapping to ‘hard code’ to Relative within Lightroom so it more closely resembles what I see when printed?
3. I thought the histogram for softproofing only shows the range that is printable, so why does relative intent show blacker blacks (lower exposure) than the Perceptual? in other words, regardless of what sliders I pull, I cannot match the same range in Perceptual intent as is suggested in Relative.
4. Since my original post I learned here that it's possible to set Intent in the Print module within Lightroom, but also export JPEG there: see Adobe settings. I'm interested to learn 4a) why would one use this over the Export option, eg would there be any quality differences? b) As far as I understand, using Relative intent changes the colour profile of the image, therefore if a user 'exports' an sRGB JPEG using Relative intent from the Print module, then would we see exactly the same image in SoftProofing the original in Relative intent in Develop module?

Answer 1

You softproof with the perceptual intent selected and edit the colors to look the way you want. It will probably be easiest to apply the edits to one image and then copy those changes to all of the other images as a general approach.

Another option is to turn on the out of gamut warnings and edit the images so that nothing is out of gamut... then relative/perceptual intent will make no difference.

Then export those images as sRGB jpegs for the purpose of being printed by that shop (maybe rename them to make that apparent).

1. yes
2. no

Edit to answer added questions:

3. Relative intent only takes out of gamut colors and changes them to the nearest in gamut color. Whereas perceptual intent changes the color to the nearest in gamut color and adjusts the other colors so they have the same relative difference. If you picture a histogram with out of gamut colors outside the ends, relative will just pull them into the very ends of the histogram leaving all of the other colors alone. Perceptual will pull them in by shifting the whole histogram. That's why relative seems darker... it's packing up the end (certain colors).

4. You cannot encode relative or perceptual, it really has nothing to do with the color profile. It is not an edit and it doesn't change the file/data in any way. It is a simulation of how the end device will handle colors that it cannot otherwise use/reproduce. The point of softproofing is so that you change the colors so that you get back something closer to what you want/expect. Your choice during softproofing does not change the fact that the end device is going to use perceptual intent (in this instance).

Normally you do not know how the end device will handle out of gamut colors; the choice of relative vs perceptual during softproofing is a personal choice in how you change the colors so that they are all in gamut... then the end device won't need to use either method and it won't matter; the end result will be as expected (hopefully). Printers typically use perceptual because relative is more prone to blocking/banding.

Generally, if there is very little out of gamut the relative intent is better, because it leaves all of the in-gamut colors alone. But if there is a whole lot out of gamut the perceptual intent is usually better because it tries to maintain the relationships between the colors. Note that changing between relative/perceptual during softproofing does not move all out of gamut colors w/in gamut; that is still your job. The image display and histogram is only simulating what the result will be if you don't. And it is only a simulation... an RGB projected display (monitor) cannot exactly duplicate a CMY reflective display (print).