Scanner Calibration w/ Macbethcal

Dear Group

I have recently attempted to calibrate my scanner using a Macbeth Color Chart in conjunction with Radiance's macbethcal. I have run into some issues with 1-3 of my colors (depending on the scanner settings) being out of gamut from reviewing by debug.pic. What I would like to know is if there is any way to rectify this situation? If not, how concerned should I be with this? I wish to use calibrated colors in order to match some of the paint color swatches that are available at many hardware stores for use in my renderings. Regarding my scanner, I am using an Epson Perfection 2480. Its a great scanner and therefore I wish not to have to replace it in order to experiment in finding another scanner that will keep the colors within gamut. As far as my scanner settings, I choose no auto exposure (selecting this option too leaves some colors out of gamut) and no color correction. Any thoughts or ideas?

Thanks

Marcus

Hi Marcus,

It is normal due to gamut issues for some saturated colors to be out of gamut. Even if macbethcal issues a warning about some moderate colors being out of gamut, it may not be a serious problem, and you should judge based on your results. If you have access to a colorimeter, you could check the RGB values against it with the xyz_rgb.cal file in the ray/src/cal/cal directory using icalc or rcalc as described in:

     http://radsite.lbl.gov/radiance/digests_html/v2n8_1b.html#COLOR_AND

I hope this helps.
-Greg

···

From: "Marcus Jacobs" <[email protected]>
Date: August 25, 2005 4:04:37 PM PDT

Dear Group

I have recently attempted to calibrate my scanner using a Macbeth Color Chart in conjunction with Radiance's macbethcal. I have run into some issues with 1-3 of my colors (depending on the scanner settings) being out of gamut from reviewing by debug.pic. What I would like to know is if there is any way to rectify this situation? If not, how concerned should I be with this? I wish to use calibrated colors in order to match some of the paint color swatches that are available at many hardware stores for use in my renderings. Regarding my scanner, I am using an Epson Perfection 2480. Its a great scanner and therefore I wish not to have to replace it in order to experiment in finding another scanner that will keep the colors within gamut. As far as my scanner settings, I choose no auto exposure (selecting this option too leaves some colors out of gamut) and no color correction. Any thoughts or ideas?

Thanks

Marcus