Brightness for print

Hi darktable specialists,
When sending my pictures for print, I’m used to brightening them a little bit compared to the “screen” variant. I usually end up doing this in digikam, on the exported full-size Jpeg.
I would ideally do that in darktable. What would you recommend as an easy solution to do that on the raw file in dt?

If you’re using the print view you can automatically apply a style before printing. If you want to export first you can do the same in the export module. See the “style” option under https://elstoc.github.io/dtdocs/module-reference/utility-modules/print/print-settings/ and https://elstoc.github.io/dtdocs/module-reference/utility-modules/lighttable/export-selected/ for details

Hi,
calibrate your screen to 120 cd/m2 (with a colorimeter) and edit your photo. optionally you could get a printer profile from your print shop, install it in darktable and activate softproof. I think the most important thing though is setting screen brightness correctly. Well and pay attention to the lighting around your screen, of course no direct light on the screen.
There should not be a significant difference in brightness between the printed photo and the photo that you view on your screen. If there is a difference, either the printer or the screen have a wrong calibration, or both, but probably your screen.
I think that is the right solution, not sure if it’s the easy solution that you are looking for.

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Thank you,
@elstoc, i like to do it per photo, some may need to be adjusted, others may not, so i can’t rely on a style.
To be clear, i send jpg or tif to a lab and i often use the proof profiles they provide, usually for the specific papers (matte…)
@betazoid maybe you are right, i should have one version regarding the brightness, and If i need to soft proof all these adjustments will be part of the softproofing anyway…

Even if they provide you with their profiles, the prints may still be way off due to the paper, lighting, inks and gamma differences to name a few reasons.

One suggestion is to find or make a profiling image or chart and send it to the printer for printing. Once you have the print, you could place it next to your screen or use a colorimeter or spectrometer to measure the colour and brightness differences. Then adjust accordingly.

Secondly, good print houses can do test prints for free. Do one for every set to make sure that the reproduction is good.

@richal you should perform calibration to match conditions at your workplace. 120 cd/m2 is simplification and could be too bright or too dark. Not to mention proper monitor…

I do not own the printer. I use professional service for prints. The printer has experience which often exceeds what can see in softproofing. He know that for given picture and given paper he should for instance brighten the image because shadows will be muddy or something like this. Keep in mind that softproofing use in calculation very specific illumination while you, most likely, will use completely different one.

The topic of printing is never ending story regardless if you use darktable, lightroom, PS or whatever. There is so many variables that can influence you final image that it is hard to get it right.

What I would recommend to you is to find a printing service (or lab) in which you are able to talk to the guy who is actually doing prints and ask if he alters the image and why.

Good luck with your prints!

Thank you for your valuable inputs. I always use the 3 same papers which are hahnemühle fine art Pearl, Baryta and Photo rag so I have several references which I use as some kind of “home-made chart”. Being used to these papers, I also have good ideas of what will go wrong: the colorimeter and spectrometer are my eyes :wink: and that is why I brighten the images: I often see on screen lots of nuances in the dark areas which I know will be all dark because of the dynamic compression of the print process.
I’m started to wonder, is my screen brightness too high?

Keep in mind that display emits light while paper reflects it. Therefore it’s hard go get apple to apple comparison between those two. And since it reflects light it strongly depends on light source, intensity and quality.

Your screen in comparison to the environment shall be neutral. The most simple evaluation is to compare white screen with white paper (could be the print your on). If those two are in your eyes equal then it’s fine. Other approach is to display on screen neutral grey (18%) and take with your smartphone a b&w photo of monitor and surroundings (https://tomaszpluszczyk.pl/wp-content/uploads/2013/09/led2.jpg - from https://tomaszpluszczyk.pl/zarzadzanie-barwa-oprogramowanie-stanowisko-obrobki-zdjec/) and then evaluate if this neutral is neutral. Oh, everything in your eyesight shall be neutral!

And then there is a print evaluation which also needs controlled environment and good light quality. Wisdom says that cloudy sky is fine.

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