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#1
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gimp and ICC color working spaces
gimp has 2 use cases
1) monitor proofing 2) print proofing yet it only has RGB and CMYK choices for working spaces I don't know if Photoshop or other software has a CIE colorimetric choice for working space, but in order to measure and track color it would be a lot easier to have one I know there are issues like gamut differences and rendering intents but if you want to measure the colorimetry of the monitor or proof and match it to the print, you need to start with CIE, not RGB or CMYK, ideally CIECAM but ICC has not gone there yet as far as I know -- Dale |
#2
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gimp and ICC color working spaces
Am 14.11.2012 05:56, schrieb Dale:
gimp has 2 use cases 1) monitor proofing 2) print proofing yet it only has RGB and CMYK choices for working spaces I don't know if Photoshop or other software has a CIE colorimetric choice for working space, but in order to measure and track color it would be a lot easier to have one I know there are issues like gamut differences and rendering intents but if you want to measure the colorimetry of the monitor or proof and match it to the print, you need to start with CIE, not RGB or CMYK, ideally CIECAM but ICC has not gone there yet as far as I know The gimp bug report and feature request list is he https://bugzilla.gnome.org/buglist.c...t%3A%22GIMP%22 |
#3
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gimp and ICC color working spaces
Thomas Richter wrote:
Am 14.11.2012 05:56, schrieb Dale: gimp has 2 use cases 1) monitor proofing 2) print proofing yet it only has RGB and CMYK choices for working spaces I don't know if Photoshop or other software has a CIE colorimetric choice for working space, but in order to measure and track color it would be a lot easier to have one I know there are issues like gamut differences and rendering intents but if you want to measure the colorimetry of the monitor or proof and match it to the print, you need to start with CIE, not RGB or CMYK, ideally CIECAM but ICC has not gone there yet as far as I know The gimp bug report and feature request list is he https://bugzilla.gnome.org/buglist.c...t%3A%22GIMP%22 There is no bug though. The "RGB" and "CMYK" labels are just that, labels for two selectable workspaces that the user can easily switch between. But the workspace assigned to either of those two labels can be 1) virtually anything the system administrator has installed and made available, or 2) anything the user chooses to install privately. Any user that wants to use a different workspace merely needs to download whatever it is and install it. In GIMP, select the Edit-Preferences-Color Management menu. Both the "RGB" and "CMYK" profile options have a selection box, and the last option in either box is to "Select color profile from disk". Once a profile has been selected it will then show up as one of the available options and choosing it will not require locating it again. Sources for such profiles include LCMS, Argyll, and others. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#4
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gimp and ICC color working spaces
On 11/14/2012 09:35 AM, Floyd L. Davidson wrote:
Thomas Richter wrote: Am 14.11.2012 05:56, schrieb Dale: gimp has 2 use cases 1) monitor proofing 2) print proofing yet it only has RGB and CMYK choices for working spaces I don't know if Photoshop or other software has a CIE colorimetric choice for working space, but in order to measure and track color it would be a lot easier to have one I know there are issues like gamut differences and rendering intents but if you want to measure the colorimetry of the monitor or proof and match it to the print, you need to start with CIE, not RGB or CMYK, ideally CIECAM but ICC has not gone there yet as far as I know The gimp bug report and feature request list is he https://bugzilla.gnome.org/buglist.c...t%3A%22GIMP%22 There is no bug though. The "RGB" and "CMYK" labels are just that, labels for two selectable workspaces that the user can easily switch between. But the workspace assigned to either of those two labels can be 1) virtually anything the system administrator has installed and made available, or 2) anything the user chooses to install privately. Any user that wants to use a different workspace merely needs to download whatever it is and install it. In GIMP, select the Edit-Preferences-Color Management menu. Both the "RGB" and "CMYK" profile options have a selection box, and the last option in either box is to "Select color profile from disk". Once a profile has been selected it will then show up as one of the available options and choosing it will not require locating it again. Sources for such profiles include LCMS, Argyll, and others. you are right, my post was not a bug report, I was trying to prompt a feature discussion RGB aand CMYK are sensitometric and densitrometric spaces respectively, and are linear withh with respect to light I was suggesting a colorimetric working space like CIELAB or CIELUV because delta E* is linear with just noticeable differences of the eye and can be measured with a colorimeter or spectrophotometer or spectroradiometer -- Dale |
#5
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gimp and ICC color working spaces
On 11/14/2012 07:11 PM, Dale wrote:
On 11/14/2012 09:35 AM, Floyd L. Davidson wrote: Thomas Richter wrote: Am 14.11.2012 05:56, schrieb Dale: gimp has 2 use cases 1) monitor proofing 2) print proofing yet it only has RGB and CMYK choices for working spaces I don't know if Photoshop or other software has a CIE colorimetric choice for working space, but in order to measure and track color it would be a lot easier to have one I know there are issues like gamut differences and rendering intents but if you want to measure the colorimetry of the monitor or proof and match it to the print, you need to start with CIE, not RGB or CMYK, ideally CIECAM but ICC has not gone there yet as far as I know The gimp bug report and feature request list is he https://bugzilla.gnome.org/buglist.c...t%3A%22GIMP%22 There is no bug though. The "RGB" and "CMYK" labels are just that, labels for two selectable workspaces that the user can easily switch between. But the workspace assigned to either of those two labels can be 1) virtually anything the system administrator has installed and made available, or 2) anything the user chooses to install privately. Any user that wants to use a different workspace merely needs to download whatever it is and install it. In GIMP, select the Edit-Preferences-Color Management menu. Both the "RGB" and "CMYK" profile options have a selection box, and the last option in either box is to "Select color profile from disk". Once a profile has been selected it will then show up as one of the available options and choosing it will not require locating it again. Sources for such profiles include LCMS, Argyll, and others. you are right, my post was not a bug report, I was trying to prompt a feature discussion RGB aand CMYK are sensitometric and densitrometric spaces respectively, and are linear withh with respect to light I was suggesting a colorimetric working space like CIELAB or CIELUV because delta E* is linear with just noticeable differences of the eye and can be measured with a colorimeter or spectrophotometer or spectroradiometer CIECAM would be better, of course you have to pick a standard CAM (appearance) for the profile connection space to convert between CAMs the current ICC perceptual connection space uses an ideal print for the CAM, this is not ideal for transparent and translucent display materials or additive systems, they have a larger gamut than a print and you have to make up information when you render from the standard CAM (the print) to these gamuts, maybe you can have choices for the standard CAM -- Dale |
#6
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gimp and ICC color working spaces
On 11/14/2012 05:29 AM, Thomas Richter wrote:
Am 14.11.2012 05:56, schrieb Dale: gimp has 2 use cases 1) monitor proofing 2) print proofing yet it only has RGB and CMYK choices for working spaces I don't know if Photoshop or other software has a CIE colorimetric choice for working space, but in order to measure and track color it would be a lot easier to have one I know there are issues like gamut differences and rendering intents but if you want to measure the colorimetry of the monitor or proof and match it to the print, you need to start with CIE, not RGB or CMYK, ideally CIECAM but ICC has not gone there yet as far as I know The gimp bug report and feature request list is he https://bugzilla.gnome.org/buglist.c...t%3A%22GIMP%22 did you say before that gimp's CMM was 8bit? 8bit encompasses the visual range of colors, but processing, to meet Nyquist would be 16bit or higher I used to make color profiles and know that few have precision of 1 delta E* I also know there is little difference between good enough color and perfect color, and that some things are better off left to editing than specification -- Dale |
#7
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gimp and ICC color working spaces
Am 15.11.2012 02:57, schrieb Dale:
CIECAM would be better, of course you have to pick a standard CAM (appearance) for the profile connection space to convert between CAMs the current ICC perceptual connection space uses an ideal print for the CAM, this is not ideal for transparent and translucent display materials or additive systems, they have a larger gamut than a print and you have to make up information when you render from the standard CAM (the print) to these gamuts, maybe you can have choices for the standard CAM First, this is a *PROFILE* connection space. It is unrelated to *PERCEPTUAL* rendering. Once more! Second, it is *UNRELATED* to ideal printing. The PCS has nothing to do with printing, rendering intent, the material you print on or its properties. Third, the PCS doesn't have a "gamut". XYZ is able to represent all colors, if you like to. |
#8
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gimp and ICC color working spaces
Am 15.11.2012 04:18, schrieb Dale:
On 11/14/2012 05:29 AM, Thomas Richter wrote: did you say before that gimp's CMM was 8bit? Yes, it's to my very knowledge . 8bit encompasses the visual range of colors, but processing, to meet Nyquist would be 16bit or higher That's not a frequency, so it's not related to *Nyquist*. But yes, depending on the steep of the tone mapping curves, you might get banding (quantization artifacts) due to the limitation of the resolution. |
#9
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gimp and ICC color working spaces
On 11/15/2012 09:03 AM, Thomas Richter wrote:
Am 15.11.2012 02:57, schrieb Dale: CIECAM would be better, of course you have to pick a standard CAM (appearance) for the profile connection space to convert between CAMs the current ICC perceptual connection space uses an ideal print for the CAM, this is not ideal for transparent and translucent display materials or additive systems, they have a larger gamut than a print and you have to make up information when you render from the standard CAM (the print) to these gamuts, maybe you can have choices for the standard CAM First, this is a *PROFILE* connection space. It is unrelated to *PERCEPTUAL* rendering. Once more! Second, it is *UNRELATED* to ideal printing. The PCS has nothing to do with printing, rendering intent, the material you print on or its properties. Third, the PCS doesn't have a "gamut". XYZ is able to represent all colors, if you like to. you are confusing the PCS with the CMM, the PCS does have rendering choices that you make on input and output profiles -- Dale |
#10
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gimp and ICC color working spaces
Am 16.11.2012 01:59, schrieb Dale:
On 11/15/2012 09:03 AM, Thomas Richter wrote: Am 15.11.2012 02:57, schrieb Dale: CIECAM would be better, of course you have to pick a standard CAM (appearance) for the profile connection space to convert between CAMs the current ICC perceptual connection space uses an ideal print for the CAM, this is not ideal for transparent and translucent display materials or additive systems, they have a larger gamut than a print and you have to make up information when you render from the standard CAM (the print) to these gamuts, maybe you can have choices for the standard CAM First, this is a *PROFILE* connection space. It is unrelated to *PERCEPTUAL* rendering. Once more! Second, it is *UNRELATED* to ideal printing. The PCS has nothing to do with printing, rendering intent, the material you print on or its properties. Third, the PCS doesn't have a "gamut". XYZ is able to represent all colors, if you like to. you are confusing the PCS with the CMM, the PCS does have rendering choices that you make on input and output profiles *Sigh*, no I'm not confusing this. I've already written CMMs, if you care. The PCS does not have rendering choices in the same sense that the R^3 does not have vector choices. It is the CMM that can implement various rendering intents. |
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