I recently revisited some RT edits of pictures which I had printed but which had appeared way too dark in parts of the image. What looked vibrant and rich in contrast on screen looks “sunken in” and lifeless in print.
After first trying to raise exposure and playing around with tone curves I ended up disabling all tools which add local contrast (I never use the Local Contrast tool itself because its effects look terrible even on screen).
I usually use Contrast by Detail Levels on the first “Contrast+” setting to increase perceived sharpness, as well as Haze Removal on a similarly low level. The effects of those two tools look great on screen when used in moderation.
However, in print, the results are invariably awful, and I believe it’s because both of these add local contrast. Going forward, I won’t be using those tools anymore, at least not as part of my RT standard toolkit.
How do you handle local contrast, and has anyone experienced similar problems when trying to print edits with tools that add local contrast?
RawTherapee is just as capable, with an extensive set of tools. This is not a PlayRaw request, but a specific question about RawTherapee. I see no reason to recommend alternative software here.
Local contrast usually darkens the dark part of your image, so maybe it looks ok on screen but doesn’t translate in print ? Sounds like screen/print mismatch to me.
The GIMP has soft-proofing for sure. I tried it and the subject got darker with lots of almost black bits … I selected AgfaSWOP from the profiles on my HD.
@Wayne_Sutton
This is a fundamental point in understanding color management, and I agree with you.
The working profile’s gamut is larger than that of the monitor (usually SRGB, sometimes Adobe, or DCI-P3, rarely higher).
The gamut of printers is often even smaller, especially in low light… especially with matte papers.
A few years ago, I worked on ICC profiles and the 468-color test chart I designed. The best printer I found was a colleague’s… Attached is the profile at L=50… Printer in ‘white’
Gloss papers can hold on to a little below RGB 6/7and still distinguish some detail, but in general, most papers begin to struggle below 12/14.
It’s worth printing a grey ramp onto the sheets in a sample pack of papers from the likes of Permajet, and then measure them with a profiler - some papers would horrify you!
Then there’s the other biggie - paper tint; something print newbies never think of. Waste of time trying to print a sunset on to a cool tint paper.
But black/dmax 0.0.0 is a futile value to have in any image - hell, even a £4000 monitor can’t actually display true black. The closest my Eizo can get to L*=0 is 2.02 - this equates to a deltaE2000 variation of just over 1, which the human eye can not discern. So L*0/RGB 0 is pointless even in a digital image, let alone a print.
I just looked at the 41-step (1/3 EV) Stouffer test wedge used by DPR for dynamic range measurement and could not distinguish any steps below about L(HSL) = 7% according to my screen color-picker on my old NEC 242 MultiSync.
Actually, though I personally use RT, I intentionally phrased my question to be open to all types of software. It was moved to the RT category by someone else, I had originally posted this in Processing. I’m asking about how others here handle any local-contrast-increasing tools/modules in any RAW processing software.
AFAIK, local contrast doesn’t simply pull down dark values globally. It adds local contrast by brightening bright parts that are next to dark parts and vice versa, based on a radius value, creating more problems than just darkening the darks. Local contrast can also easily create ugly bright halos.
For example in this image, local contrast would brighten the sky right next to the dark cables, with a gradual fall-off based on the radius value.
G’MIC has a lot of detail presets that does the trick. One is actually called local contrast enhancement. Highly recommend G’MIC if you don’t have it already. I use the GIMP filter, but there’s also command line version that other swear by. Someone even ported G’MIC as a photo-shop compatible plugin.
