Printing RGB and sRGB image files

richard cooper

Newbie

Posts: 24

« on: May 26, 2011, 03:17:15 PM »

Does Qimage convert RGB and sRGB to CMYK for printing?

Does this depend on what ink jet printer is being used?

Thank you
Richard


	Logged

Terry-M

The Honourable Metric Mann
Forum Superhero

Posts: 3251

Re: Printing RGB and sRGB image files

« Reply #1 on: May 26, 2011, 03:43:09 PM »

Hi Richard,
Qimage is an RGB application and does not handle CMYK profiled images therefore I would think it does not convert any RGB image to CMYK and leaves that task for the printer driver to do.
What Qimage does do is to convert from the image RGB icc profile to the RGB icc printer profile. It is a colour management aware application.
Terry.
PS. I should have said Qimage converts from any image "RGB" profile; eg. I print from raw in Qimage where the profile is my camera profile. Non raw images do need to have exif tagging or (preferred) an embedded profile for Qimage to recognise it correctly. T


« Last Edit: May 26, 2011, 03:49:47 PM by Terry-M »	Logged

richard cooper

Newbie

Posts: 24

Re: Printing RGB and sRGB image files

« Reply #2 on: May 26, 2011, 04:49:19 PM »

Hi Terry, thanks for this information.

To clarify, I set my Sony A850 camera to RAW and tag the image sRGB. (Colors look better on my calibrated monitorThan RGB). I convert the image in the Sony RAW converter using sRGB color working space.

I then save the converted image as sRGB and will be testing using both 8bit and 16bit for print with my Epson Stylus Photo printer.

The reason for the question, I thought I read that Qimage acted similar to a RIP and converted the file to CMYK for printing.

Richard


	Logged

Terry-M

The Honourable Metric Mann
Forum Superhero

Posts: 3251

Re: Printing RGB and sRGB image files

« Reply #3 on: May 26, 2011, 04:54:50 PM »

Quote

I then save the converted image as sRGB and will be testing using both 8bit and 16bit for print with my Epson Stylus Photo printer.

You are probably wasting you time with 16 bit images wrt printing; Qimage does not do 16 bit images and converts to 8 bit anyway.
See Mike's articles here http://ddisoftware.com/tech/articles/september-2009-digital-photography-reality-check-308/
Terry


	Logged

Terry-M

The Honourable Metric Mann
Forum Superhero

Posts: 3251

Re: Printing RGB and sRGB image files

« Reply #4 on: May 26, 2011, 08:33:04 PM »

Richard,
More information.

Quote

To clarify, I set my Sony A850 camera to RAW and tag the image sRGB. (Colors look better on my calibrated monitor than RGB).

A raw image does not have a colour space except that of the camera. It is converted to sRGB or Adobe RGB, or others possibly, (your choice) by the raw software when the raw image is converted to tiff, jpeg etc.
If you are looking at an image in the Widows viewer, then the colour will not look right for Adobe RGB because it's not colour management aware. I must admit I'm not too sure about that on Windows 7 but XP never converted to the monitor profile. If you have Qimage set up with your monitor profile and the images is tagged or has an embedded profile, you will see the correct colour rendition.
Adobe RGB does have a larger colour gamut that sRGB so that is usually recommended when comparing the two.
If you used Qimage Ultimate for raw processing, then you have the choice of sRGB, Adobe RGB or your camera profile although I don't think one is available for your camera at present. No conversion is need to another format, just print from the raw file.

More about CMYK for printers - I've checked with an expert and it's now years out of date because all good photo printers have more than Cyan, Magenta, Yellow & Black; mine has 8 cartridges! The driver does the conversion for the particular printer.
Terry


	Logged

Pages: [1]

« previous next »