Using Online Photo Printers on Images from GIMP

Processing
1

I am looking for recommendations on which online photo printer(s) do the best job of matching images edited in GIMP and saved with the GIMP sRGB profile. I have used Mpix for several photos, and have seen some difference between what I see onscreen and what I receive from them, which I don’t expect to eliminate entirely, but to minimize as much as possible.

My monitor is a six-year-old HP LA2405wg, which I bought because of the 16:10 display ratio. I have used aids from online to calibrate it. I haven’t invested in profiling/calibration equipment yet because I don’t think I have reached the level of competence to justify the investment. When I reach that point, I plan to get a new monitor and/or profiling/calibration equipment.

I use the Mpix provided profile to soft-proof, but I don’t have the knowledge and skill to pull the out of gamut areas back into gamut. I have also used profiles from Bay Photo Lab and Nations Photo Lab, but have not had anything developed by them yet. I see differences in the areas marked out of gamut among them.

My camera is a Canon PowerShot G9X Mark II. I process the raw images with darktable, Raw Therapee, and sometimes Canon’s Digital Photo Professional 4.

Finally, I have read many articles on color management. Most of the information, though, is related to doing things that are beyond the scope of my equipment at the moment.

2

Hi @Underexposed,

Sorry, there is no easy way out of your dilemma.
A print profile depends on a specific combination of printer+ink+paper
used. Change one parameter and the profile will not be valid any more.

You could develop a print at your place and send it off for printing.
When you get the result back, try to alter your image to make it look like
the print.

This is a quagmire:

Have fun!
Claes in Lund, Sweden

1 Like
3

This might get you close, but that’s about it. You really need a hardware calibration unit before you can move beyond where you are now. Your eyes will fool you in certain situations!

1 Like
4

I took a look at some prints and compared them to the soft-proofed versions, and I see more color variation and brightness variation than I remembered. I don’t print at home. I see that I am so far off that investing in hardware calibration is a necessity. Once I see where I truly am, I can work on correcting it.

5

it is partly a difference between projected light (your monitor) and reflected light (the print). Same as back in the day when looking at slides being projected vs prints. The slide looks better than the print, brighter colors and all.

1 Like
6

I have noticed that when I soft-proof, there is almost no change except that with a couple of the profiles it appears that contrast has been lowered. When I mark out of gamut areas, some areas are indicated. As a test, I loaded my monitor profile as the soft-proof profile. No change whatsoever in the image, as expected, but no areas show up as out of gamut. If there is virtually no change in color and brightness when I compare the Mpix profile to my monitor profile, but there are differences in what is out of gamut, what does that tell me?

Incidentally, Claes, I followed up on that link of yours, and followed up on links in those articles, and my head is swimming. Quagmire doesn’t express it.

7

I’d like to come closer in my prints to what I see on the screen, but does calibrating fix that. My guess is no. Seems like on-screen images would have to be highly saturated and with increased exposure to end up printed like the on-screen version I want to see.

8

What makes you think that calibrating won’t fix your issue?

9

@Underexposed keep in mind that softproof is only a hint. It will not show you how the print will look like but gives you rough idea. Also note that softproof emulates print which is being viewed at specific conditions (something like this: PDV Professional Desktop Viewers - GTI Graphic Technology Inc.). Thus when viewed at home it may look different, especially in artificial lighting (color shifts may occur here). You need preferably full spectrum light to evaluate your print.
Some online printing services offers printed targets and dedicated JPGs which are matched thus you may see how the print matches your screen.
Calibration of the screen is highly recommended! The brightness of the screen must be matched to your working environment. We have here even a discussion how DT theme (the same with gimp) may affect brightness of your photo. It all counts.

10

I might have been wrong to say that, but since then I have looked at the photo on my wife’s iPad, and it looks the same as what is on my screen. If my calibration was significantly off, wouldn’t there be differences?

I loaded the jpg my camera produced into GIMP and soft-proofed it; there was more out of gamut area than with my image. I tried it with the two other profiles I’ve downloaded, and there was less than with Mpix, but still significant areas of out of gamut. Why would online developers sRGB be so different than that used by my Canon?

I researched calibrators and am of the opinion, that even though it is more expensive, it pays to buy the more expensive models. I am looking at getting a i1Display Pro.

11

i1Display Pro is expensive but for what it offers is still a bargain. It’s far better than competitors in this price range.

Try this:
http://www.frogymandias.org/gamuts/make-3d-plots.html

and use your paper profile against sRGB. See how those 2 gamuts differ (change -ir to -ip to have perceptual rendering intent).

Display’s white can burn your eyes while paper’s white is just a plain paper.
Display’s black can be really black while paper’s black is just black ink on it. Shadows in print will use black ink thus the gamut will be reduced.
I print on a service which uses 12 pigments (Canon iPF8400) and still I need to correct almost all photos.
Printing is hard but it’s it a great pleasure to hold a good print on a good quality paper. It will last for ages!

12

@maf

I might have seen that discussion; at any rate, I switched to the gimp gray theme awhile back.

I think I will try increasing the exposure by various amounts and having those printed. I also discovered in my notes that I produced a version of the photo in which I decreased contrast until all the out of gamut areas went away. I’ll try having that printed.

13

So that’s how those images are made.

What service do you use? When you say correct, what do you mean?

14

If you have lowered the contrast then you increased the shadows and decreased the highlights. This is mainly the procedure :slight_smile: Avoid artificial colors. They may not map into any combinations of ink - they may not be reproducible on print especially when saturated.

What I do? I try to visualize the gamut (link above) and see what are the shadows and highlights.
On softproof (with proper rendering intent selected and bkp compensation on) I selectively increase shadows and most often desaturate them a bit. Most of the time shadows are my problem. Very often desaturation of shadows gives no visual effect but out-of-the-gamut warning is gone.
I’m printing on fine art papers on studiogamut.pl. I can reach the operator when necessary or give comments to order. The quality is very good. But nonetheless I have many prints I’m not satisfied thus I try and I try. For me it’s still cheaper than buying epson 3880/p600/whatever or canon printer since I print in batch rather infrequently.

15

Calibration is about making known, measurable colors display correctly. After I calibrated, my screen looked “worse,” less saturated and sort of dull. But the colors matched my printer exactly.

16

@paperdigits

I ordered the i1Display Pro; be here tomorrow. This will be interesting.

@maf

I have noticed that the oog areas are in the shadows. How do you select them, the Select by Color Tool? I will dig into learning how to make those graphs. I am very interested in seeing how the gamuts differ. I’ll have to see if Mpix has a paper profile file. I do use bkp compensation, and I use Elle Stone’s methods to keep everything within gamut, that is, the gimp sRGB gamut.

I take it you are located in Poland, or at least in Europe?

I appreciate the advice you guys have been giving me. Thanks.

17

@Underexposed I use DT mainly so I can use Color Balance module or filmic for overall corrections. For more precise ones I will use Tone curve/Color zones with parametric masks. I switch almost exclusively to DT after discovering that I can crop the way I want and use framing module to have desired output format.

For Fine Art prints corrections are usually minor especially if baryta paper is used. For matt it needs a bit more intervention.
Now I struggle with Mohawk Eggshell matt paper printed with HP Indigo and it’s pain in the … back. But the paper is nice so I guess it will be worth the effort.

Can you please link me to the Elle’s article?

18

@maf

I have only used DT for raw processing to provide a neutral image to GIMP. I am working through various examples I have found online, e.g., by Pat David, but I only know that parametric masks exist. I want to learn more when I have time.

There’s a couple articles you might find interesting. The first is:
https://ninedegreesbelow.com/photography/gimp-tone-map-with-levels.html
The part you want to look at in particular is:

B. A worked example showing how to recover shadow information using high bit depth GIMP’s floating point “Colors/Exposure”.
But the rest of it is also very useful to read. The technique may not suit your aesthetic intentions, but it is nice to know about it.

Another article is:
Autumn colors: An Introduction to High Bit Depth GIMP’s New Editing Capabilities
https://ninedegreesbelow.com/photography/high-bit-depth-gimp-tutorial-edit-tonality-color-separately.html#curves-clclips

In section B. Edit for Chroma, you don’t have to use Channel Mixer to adjust Chroma on other images, you can use Colors/Hue-Chroma.

In step B.3.4. Make and add a “Chroma mask” to the “Visible + Channel mixer to add Chroma” layer, There are three pictures illustrating that step. The one on the right says use Auto Stretch Contrast, but the text omits that step. Do it according to the pictures.

Down lower, in section E. Out of gamut colors: Why they are important and how to deal with them, Elle talks about handling oog colors. I just noticed something that I apparently have been doing wrong, section E2. Editing at floating point requires soft proofing before exporting the final image to disk:

“The gamut checks don’t give accurate results for linear gamma images, so for accurate soft proofing you need to make a flattened copy of the final image and convert it to to a color space with a perceptually uniform TRC.”

Now I have to figure out how to convert to a color space with a perceptually uniform TRC. I wonder if that is done simply by Image/Precision/Perceptual gamma (sRGB)?

One more article about Chroma: Three ways to modify saturation using GIMP 2.9/2.10 LCH color tools
https://ninedegreesbelow.com/photography/changing-saturation-using-lch-chroma.html

Enjoy reading.

19

@Underexposed thank you for the links. I have seen those links but I’ve never managed to actually read it. Maybe I will soon :slight_smile: