Brightness/Contrast settings have no effect

Questions on certain printers and applications
Post Reply
docrob
Posts: 12
Joined: Mon Sep 28, 2009 10:08 am

Brightness/Contrast settings have no effect

Post by docrob »

This is a similar problem to that reported by mardan56 in Feb 2010 but was not resolved in that thread. He posted in "Linux Distributions", but I don't think it is distro related, hence posting here.

I have been using TP successfully for a couple of years on an HP PhotoSmart Pro B9180, printing via Qimage. The default settings were OK on that printer, but when it stopped working I got a replacement B9180 from HP. With exactly the same settings, the colours are spot on but there is significant loss of detail in the shadows. I have tried Brightness and Contrast from one extreme to the other, but there is no perceptible difference in the prints. The colour space is sRGB, intent is Perception, although the same applies with Perception Inksave. Quality is set to Super - 4800dpi and Paper to HP coated paper. Qimage is set to "Let printer driver manage color".

I have verified that changes to the Brightness, Contrast etc are reflected in the turboprint.cfg file. Although I cannot find any documentation on this file, I have also tried changing the "Shadows" setting manually, on the assumption that it has something to do with the experimental zedoShadows function, but again, no effect. For completeness, I am using OpenSUSE 11.4 (Linux 2.6.37.6-0.9-desktop x86_64), KDE 4.6.0. I upgraded to TP 2.23-1, but it made no difference.

I would be very grateful for some help on this; I have some urgent prints to do, with lots of contrast and shadow detail and at the moment the results are unusable.
zedonet
Site Admin
Posts: 2156
Joined: Fri Oct 06, 2006 8:02 am

Re: Brightness/Contrast settings have no effect

Post by zedonet »

Hello,

there was a similar bug that was fixed in TurboPrint 2.17: sometimes color correction settings had no effect when printing from the GIMP TurboPrint plugin.

Can you please post the log file /var/log/turboprint/print.log (or email to: mail at zedonet dot com) after making 2 prints with different "Brightness" & "Contrast" settings so that I can see if the settings are properly transmitted to the printer driver?

Please include information how the brightness & contrast sliders were set for the first and second print.
docrob
Posts: 12
Joined: Mon Sep 28, 2009 10:08 am

Re: Brightness/Contrast settings have no effect

Post by docrob »

Thank you very much for your help. That's one thing I didn't think to do.

I have attached the log files in a separate email, with the same title. I tried everything I could think of, but no filenames seemed to be acceptable to upload here. print.log_1 has settings at mid-position and print.log_2 with Contrast at minimum and Brightness at maximum. print.log_1 incorporates two print jobs: the first was completed and printed, the second was sent to the printer, then cancelled. print.log_2 print job was also cancelled after being sent to the printer. I have attached the corresponding turboprint.conf files, similarly numbered.

It appears to me that the turboprint.conf file is being correctly updated, but the log files do not reflect the changes. There is no way I can find to access the Shadows parameter via the normal interface, but I did change this manually in turboprint.conf, again with no observable effect. If this were to work, I believe it would be the best parameter to use in this case, as the highlights and mid-tones are fine; it's just the shadow detail which is not there.
zedonet
Site Admin
Posts: 2156
Joined: Fri Oct 06, 2006 8:02 am

Re: Brightness/Contrast settings have no effect

Post by zedonet »

Thank you for the logfiles! The settings are present in the config file, but are not transmitted to the printer driver. This problem might be specific for the application software you are printing from.

Which software did you use to print (I don't know of a Linux version of Qimage)?

Can you adjust brightness & contrast when printing from other applications, e.g. from gwenview?
docrob
Posts: 12
Joined: Mon Sep 28, 2009 10:08 am

Re: Brightness/Contrast settings have no effect

Post by docrob »

Thanks again for your reply. I agree the settings in the config file are not reflected in the log file.

You are right in that Qimage is an MS Windows program; however, it runs perfectly on Linux under WINE and I have been using it successfully for some time.

I was surprised at your suggestion that it could be application dependent as I do not know of a mechanism by which the application would be able to do this. As far as I am aware, the application passes its information to the driver, which then applies whatever corrections are set therein and creates the print file. Nevertheless, I tried printing from Gwenview but the problem remains: there is no variation in the print when the brightness and contrast are moved from one extreme to the other. Furthermore, as with Qimage, the config file is duly modified but the log file is unchanged. I did notice incidentally that the log file does correctly reflect changes to the "Intent" setting.

I am very puzzled, because if this problem were widespread I would expect others to have shouted before now!
docrob
Posts: 12
Joined: Mon Sep 28, 2009 10:08 am

Re: Brightness/Contrast settings have no effect

Post by docrob »

I wondered whether anyone had made any progress on this issue.

I upgraded to version 2.24-1 but this had no effect on the problem; I wasn't expecting it to, judging by the version history. If no solution can be found, the only alternative would seem to be to do a new profile for the printer and let the printing application - Qimage - take care of the colour management. I had every intention of doing this anyway, but now I am concerned as to whether I could achieve a satisfactory result by this means, and also what would happen if I wanted to "tweak" the colours a little.

It is very strange that the changes to most of the settings are not passed to the driver and yet the "Intent" setting is reflected in the log file.
docrob
Posts: 12
Joined: Mon Sep 28, 2009 10:08 am

Re: Brightness/Contrast settings have no effect

Post by docrob »

Still an ominous silence on this problem.

I have a little more information now. I upgraded OpenSUSE to 12.1 by a clean install, so everything, including Turboprint, was reinstalled. However, I have exactly the same problem - no change.

In desperation, I pulled out an old Windows XP machine, installed the HP driver and Qimage, then did some test prints. Using the HP driver to control the colour (i.e. no application control) for direct comparison, I did some test prints with preset profiles for several different photo papers. The results were very acceptable and certainly as good as could reasonably be expected without specific profiles for the printer. The colours were fairly accurate and the shadow detail excellent.

I cannot understand why Turboprint produces such poor results now, when previously it was very good. If anybody can suggest a solution, or more tests for me to carry out, I would be grateful, otherwise I will have to abandon Turboprint and use a Windows machine for all my printing - very far from ideal.
zedonet
Site Admin
Posts: 2156
Joined: Fri Oct 06, 2006 8:02 am

Re: Brightness/Contrast settings have no effect

Post by zedonet »

I guess that Linux printer driver settings don't work correctly for applications running under Wine. It might help to change the system default settings of the printer driver instead of the user settings. This can be done by running TurboPrint Control as "root", e.g. from a terminal window with

sudo turboprint
docrob
Posts: 12
Joined: Mon Sep 28, 2009 10:08 am

Re: Brightness/Contrast settings have no effect

Post by docrob »

Thanks for your suggestion about the system default settings, which I will have a go at as soon as I can and report back. The indications are that the problem is not down to programs running under WINE, however. You asked me earlier to test Turboprint with native Linux programs e.g. Gwenview, which I did and had exactly the same problem. I will try with other Linux programs - GIMP and Digikam come to mind as suitable candidates.
docrob
Posts: 12
Joined: Mon Sep 28, 2009 10:08 am

Re: Brightness/Contrast settings have no effect

Post by docrob »

Well, that was an interesting exercise! I had some results I cannot explain, but I think the problem is resolved to a degree I can live with. It now appears you were probably on the right track with a Qimage/WINE problem, but I have summarised the results below in case it helps anyone else.

1. Before making any changes, I briefly repeated the tests with Qimage, and also with GIMP instead of Gwenview, with the same results - no change to the log file.
2. I opened a terminal session as root and set new defaults as you described, with brightness and contrast (B & C) at their extremes.
3. As an ordinary user, I printed from GIMP via Turboprint. The log file recorded the new defaults set by root. I could then change the brightness and contrast settings in the Turboprint UI and these were correctly and consistently reflected in the log file. These settings were not saved when the print dialogue box was closed, so that the default (extreme B & C) settings were shown whenever the Turboprint Control was reopened.
4. As an ordinary user, I switched to Qimage and sent a print. Again, the root defaults were reflected in the log file. I changed the B & C settings and as with GIMP, these also changed accordingly in the log file, but only once; subsequent adjustments to B & C had no effect and the log file remained unchanged.

I conclude that there does appear to be a problem with Qimage running under WINE, although I cannot explain either why the B & C settings did respond once, or why the Intent setting responds consistently. Neither can I explain why the Linux programs Gwenview and GIMP had the same problem until I reset the defaults as root. It would be nice to get Turboprint working properly with Qimage, but ultimately, there is a work-around, if cumbersome, by opening a root session to make the desired adjustments. I think it is now worth getting an ICC profile done, as I have some confidence it will work properly. It also remains a mystery why the results with the first printer before it failed were good (and virtually identical to the results from Qimage on Windows, using the HP driver), but those with the second, despite the printer's closed-loop calibration, are unacceptable.

Thank you again for your help on this and I look forward to being able finally to get some quality prints once I have obtained a profile for the printer.
Post Reply