BTW, I am not able to get a duotone image with recent minimals in the example published here: http://wiki.contextgarden.net/Colors#Colorizing_Grayscale_Pictures \setuplayout[header=0pt,footer=0pt,width=middle,height=middle,backspace=1cm,topspace=1cm] \setupcolors[state=start] \startbuffer \definecolor [blue] [c=1, m=.38, y=0, k=.64] \definecolor [yellow] [c=0, m=.28, y=1, k=.06] \definespotcolor [blue-100] [blue] [p=1] \definespotcolor [yellow-100] [yellow] [p=1] \definemultitonecolor [combicolor] [blue=.12, yellow=.28] [c=.1, m=.1, y=.3, k=.1] \definemultitonecolor [combicolor-b] [blue=1] [c=1, m=.38, y=0, k=.64] % force multitone \definemultitonecolor [combicolor-y] [yellow=1] [c=0, m=.28, y=1, k=.06] % force multitone \useexternalfigure[demo-a][mill.png] [object=no, width=.2\textwidth] \useexternalfigure[demo-b][hacker-bw.jpg][object=no, width=.2\textwidth] \startbaselinecorrection \startcombination[4*1] {\externalfigure[demo-a]} {no color} {\externalfigure[demo-a][color=combicolor]} {indexed duotone} {\externalfigure[demo-a][color=combicolor-b]} {spot color} {\externalfigure[demo-a][color=combicolor-y]} {spot color} \stopcombination \stopbaselinecorrection \startbaselinecorrection \startcombination[4*1] {\externalfigure[demo-b]} {no color} {\externalfigure[demo-b][color=combicolor]} {indexed duotone} {\externalfigure[demo-b][color=combicolor-b]} {spot color} {\externalfigure[demo-b][color=combicolor-y]} {spot color} \stopcombination \stopbaselinecorrection \startbaselinecorrection \startcombination[4*1] {\externalfigure[demo-a]} {no color} {\externalfigure[demo-a][color=combicolor]} {indexed duotone} {\externalfigure[demo-a][color=blue-100]} {spot color} {\externalfigure[demo-a][color=yellow-100]} {spot color} \stopcombination \stopbaselinecorrection \startbaselinecorrection \startcombination[4*1] {\externalfigure[demo-b]} {no color} {\externalfigure[demo-b][color=combicolor]} {indexed duotone} {\externalfigure[demo-b][color=blue-100]} {spot color} {\externalfigure[demo-b][color=yellow-100]} {spot color} \stopcombination \stopbaselinecorrection \stopbuffer \getbuffer \typebuffer \stoptext The images in the column "indexed duotone" do not show up. Piotr 2009/7/7 Hans Hagen :

Piotr Kopszak wrote:

...

Hello list,

I am preparing for a next project which will be printed in two colours. Obviously, perfect opportunity to use duotones. However I got my duotone illustrations in CMYK tiffs with images in yellow and black channels. Obviously black could stay but I would like to convert the yellow channel to the spot colour I am going to use. Any ideas (without using Photoshop) ?

as it is possible to colorize bw bitmap images in context i suppose that doing the same with a dual channel image is doable as well but i never tried is (low on my list of priorities so you're unlicky that we never needed that variant in projects)

Hans

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I can't get it right with mkii and xetex either. Piotr 2009/7/9 Hans Hagen :

Piotr Kopszak wrote:

...

BTW,

I am not able to get a duotone image with recent minimals in the example published here: http://wiki.contextgarden.net/Colors#Colorizing_Grayscale_Pictures

the current public version of mkiv does not provide it (beta does but that one is not yet posted)

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-- http://okle.pl

Yes, but I don't arrive at expected results with pdftex either. Piotr 2009/7/9 Hans Hagen :

Piotr Kopszak wrote:

...

I can't get it right with mkii and xetex either.

forget about xetex; mkii uses a pdftex feature (access to resource dict)

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-- http://okle.pl

Many thanks for all replies, Well, maybe someone comes up with a solution one day. It would be nice to have a complete Photoshop-less production environment on linux. BTW, can tif support spot colors at all, I haven't found any mention of that anywhere, hence I don't think libtiff might be of use. Piotr 2009/7/7 William Adams :

On Jul 7, 2009, at 9:50 AM, Piotr Kopszak wrote:

...

I am preparing for a next project which will be printed in two colours. Obviously, perfect opportunity to use duotones. However I got my duotone illustrations in CMYK tiffs with images in yellow and black channels. Obviously black could stay but I would like to convert the yellow channel to the spot colour I am going to use. Any ideas (without using Photoshop) ?

Leave the images be, set the things you want to appear in the spot colour as yellow, then tell the printer that the yellow plate is the spot colour and to suppress cyan and magenta.

Or use the spot colour and tell the printer to merge the yellow plate w/ the spot colour (check first --- while all RIPs should be able to do this, not all printers will be willing to).

Or use Enfocus PitStop to post-process the .pdf.

However, unless the spot colour is _very_ light, I doubt that you'll be able to use the images as is --- they'll probably print too dark, so you'll need to process them anyway. I'd make a PhotoShop action to convert the images to multi-channel, then change the yellow plate to the spot colour, then apply a curve to lighten the spot colour, then save the image (but make sure you keep an original), then I'd use a second action to review all of the files on a calibrated monitor, tweaking as necessary and going back to original images at need.

William

-- William Adams senior graphic designer Fry Communications Sphinx of black quartz, judge my vow.

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On Wed, Jul 8, 2009 at 3:39 PM, William Adams wrote:

On Jul 7, 2009, at 1:20 PM, Piotr Kopszak wrote:

BTW, can tif support spot colors at all, I haven't found any mention

...

of that anywhere, hence I don't think libtiff might be of use.

One can only get spot colours for a bitmap into a .eps (or .pdf) or .psd.

What one could do using libtiff is split the channels of the file, toss magenta and cyan,

hmm how do you do it ? -- luigi