Hello all,
My name is Don Isbell, Jr.
I have not been in prepress or printing for about a year now (I am now a Forex trader, Don Isbell, Jr. | LinkedIn), but was looking at an Excel document that I made years ago, and converted to Apple Numbers.
Background:
I've kept up with GRACoL since its beta stage, and although this is old stuff, it is and will be relevant in the future as time passes. I figure for many the Excel doc and understanding the graphs may be new, and helpful, so I am posting it here.
Understanding the graph:
INDEPENDENT OF PAPER DENSITY, there are CURVES (named Neutral Print Density Curve, or NPDC, that Don Hutcheson, www.hutchcolor.com, who also chaired GRACoL, and introduced NPDC to the community).
After seeing that SWOP separations could be printed without color managing CMYK, on coated (GRACoL2006_Coated1v2) or uncoated (Beta Uncoated 2009), and appearance between SWOP and GRACoL separations when printed on GRACoL, plus U.S. and Europe appearance was so close (within a couple percent), I was satisfied with my research.
Also, through experience I honored embedded RGB profiles, and used sRGB IEC61966-2.1 profile for RGB images received that has no ICC profile embedded, and had no color problems
Bottom line, I was able to easily implement GRACoL by first getting within LAB tolerances for solid C-M-Y-K-CM-CY-MY using an Eye-One with no filtration, then easily using the graph/the DENSITIES WITHOUT PAPER to GET my TARGETS, and getting TO those ON PRESS with a densitometer SET to give readings SUBTRACTING paper.
Consequently, this math is SO precise that it shows how the official ICC profiles FOR EACH PAPER TYPE could be tweaked to better conform to the NPDC for that particular paper type and density range that the paper has (in fact, most color "problems" come down to coated papers can hold higher densities and result in brighter colors than is possible on uncoated paper). COMMON PROBLEM: MISUNDERSTANDING BY PRINTER AND/OR CUSTOMER OF WHAT IS ACHIEVABLE ON UNCOATED PAPERS AND THEY MAY NEED TO USE COATED PAPER AND NOT UNCOATED TO GET TO THEIR COLOR.
This graph and the target densities at 25, 50, and 75%, with VISUAL way that these ICC profiles interact with graph of GRAY DENSITY is basically one tool that can be used to not only understand color and printing, but can be used to correct printing too.
You can get the original Excel document (in Excel format) at:
COMPARE NPDCs - DON HUTCHESON FORMULA.xls - 4shared.com - online file sharing and storage - download
COMPARE NPDCs 2009.xls - 4shared.com - online file sharing and storage - download
TVI 2009-ADOBE GRACOL TO GRACOL.xls - 4shared.com - online file sharing and storage - download
TVI 2009R-ADOBEGRACOL TO GRACOL.xls - 4shared.com - online file sharing and storage - download
There are others I made, but I can't find them, and they are superfluous.
Thanks goes to Don Hutcheson for making this available freely to the community, so that we can get to ISO standards in a more precise way, even more precise than ISO defines Thanks to Don for doing what he could to get us on the same page. I am just a lover of color, and tested and verified for myself and the community what Don was putting forth. I like it a lot. I could be a color consultant, but would rather trade. I hope these documents help you, like Don did, and like I have always tried to do on here when I participated - given freely - and I just love math, so checked his math and see the great benefit of G7 process/graphs.
You'll also see that I use TVI (tone value increase aka dot gain) to compare Adobe and GRACoL ICC profiles using math from color scientist Bruce Lindbloom, www.brucelindbloom.com. These are ONLY VALID for comparison of TVI from two papers with these characteristics:
Printed solids and paper color with very close LAB values between the two papers.
I just like TVI (I'm old school), but see it also is not necessary with the NPDC graphs. So it's here FOR TEACHING/COMPARISON PURPOSES ONLY.
Kind regards,
Don
My name is Don Isbell, Jr.
I have not been in prepress or printing for about a year now (I am now a Forex trader, Don Isbell, Jr. | LinkedIn), but was looking at an Excel document that I made years ago, and converted to Apple Numbers.
Background:
I've kept up with GRACoL since its beta stage, and although this is old stuff, it is and will be relevant in the future as time passes. I figure for many the Excel doc and understanding the graphs may be new, and helpful, so I am posting it here.
Understanding the graph:
INDEPENDENT OF PAPER DENSITY, there are CURVES (named Neutral Print Density Curve, or NPDC, that Don Hutcheson, www.hutchcolor.com, who also chaired GRACoL, and introduced NPDC to the community).
After seeing that SWOP separations could be printed without color managing CMYK, on coated (GRACoL2006_Coated1v2) or uncoated (Beta Uncoated 2009), and appearance between SWOP and GRACoL separations when printed on GRACoL, plus U.S. and Europe appearance was so close (within a couple percent), I was satisfied with my research.
Also, through experience I honored embedded RGB profiles, and used sRGB IEC61966-2.1 profile for RGB images received that has no ICC profile embedded, and had no color problems
Bottom line, I was able to easily implement GRACoL by first getting within LAB tolerances for solid C-M-Y-K-CM-CY-MY using an Eye-One with no filtration, then easily using the graph/the DENSITIES WITHOUT PAPER to GET my TARGETS, and getting TO those ON PRESS with a densitometer SET to give readings SUBTRACTING paper.
Consequently, this math is SO precise that it shows how the official ICC profiles FOR EACH PAPER TYPE could be tweaked to better conform to the NPDC for that particular paper type and density range that the paper has (in fact, most color "problems" come down to coated papers can hold higher densities and result in brighter colors than is possible on uncoated paper). COMMON PROBLEM: MISUNDERSTANDING BY PRINTER AND/OR CUSTOMER OF WHAT IS ACHIEVABLE ON UNCOATED PAPERS AND THEY MAY NEED TO USE COATED PAPER AND NOT UNCOATED TO GET TO THEIR COLOR.
This graph and the target densities at 25, 50, and 75%, with VISUAL way that these ICC profiles interact with graph of GRAY DENSITY is basically one tool that can be used to not only understand color and printing, but can be used to correct printing too.
You can get the original Excel document (in Excel format) at:
COMPARE NPDCs - DON HUTCHESON FORMULA.xls - 4shared.com - online file sharing and storage - download
COMPARE NPDCs 2009.xls - 4shared.com - online file sharing and storage - download
TVI 2009-ADOBE GRACOL TO GRACOL.xls - 4shared.com - online file sharing and storage - download
TVI 2009R-ADOBEGRACOL TO GRACOL.xls - 4shared.com - online file sharing and storage - download
There are others I made, but I can't find them, and they are superfluous.
Thanks goes to Don Hutcheson for making this available freely to the community, so that we can get to ISO standards in a more precise way, even more precise than ISO defines Thanks to Don for doing what he could to get us on the same page. I am just a lover of color, and tested and verified for myself and the community what Don was putting forth. I like it a lot. I could be a color consultant, but would rather trade. I hope these documents help you, like Don did, and like I have always tried to do on here when I participated - given freely - and I just love math, so checked his math and see the great benefit of G7 process/graphs.
You'll also see that I use TVI (tone value increase aka dot gain) to compare Adobe and GRACoL ICC profiles using math from color scientist Bruce Lindbloom, www.brucelindbloom.com. These are ONLY VALID for comparison of TVI from two papers with these characteristics:
Printed solids and paper color with very close LAB values between the two papers.
I just like TVI (I'm old school), but see it also is not necessary with the NPDC graphs. So it's here FOR TEACHING/COMPARISON PURPOSES ONLY.
Kind regards,
Don
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