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Convert Color Images to Grayscale

Rorohiko (“Lightning Brain”) recently released a free beta of an InDesign plug-in that converts color bitmapped images (such as TIFF, JPEG, and PSD) to grayscale. Actually, more accurately, you have to install three plug-ins to make it work, but it’s easy to do (just download a file from their Web site and then drag the plug-ins into the Plug-ins folder inside your Adobe InDesign folder).

Many people have asked me about a feature like this in InDesign because QuarkXPress has an option to convert color images to grayscale at import time. How does this plug-in work? I know it’s based on an underlying hidden JavaScript, but I can’t tell what strings it’s pulling for the conversion. It appears to be magic.

But it’s not perfect magic: For example, transparency in an image apparently is not supported in this version, so pictures become opaque. Also, as the folks at Rorohiko are quick to point out, this plug-in offers no controls for how an image is converted (there are lots of ways to convert color images to grayscale; see Real World Photoshop).

I haven’t tested this plug-in extensively, but it does appear to work quickly and all results end up on the black plate of color separations. No word on whether this plug-in will remain free or will cost money when it’s finished.
Rorohiko also makes a bunch of other free (and commercial) plug-ins, including one that exports all your document text into a single file, one that makes an InDesign library out of a folder full of images, and (one of my favorites) something called ChatterGoofy, which is a replacement for QuarkXPress’s Jabberwocky XTension.

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36 Comments on “Convert Color Images to Grayscale

  1. Hi Dave,

    Thanks for the nice comments!

    A few clarifications: the ‘magic’ is not done in JavaScript – it’s done by a ‘real’ plug-in (for the C++ geeks: it goes by the name of ‘custom draw event handler’ – it’s one of the three plug-ins you need to install).

    It intercepts InDesign’s redraw operation of the image, and instead redraws the image in grayscale, even if the original is in color.

    On the other hand, the user-interface part is pure JavaScript wrapped into a scripted plug-in.

    As for cost – this plug-in will remain free. We might do a commercial ‘extended version’ with more bells and whistles if we see there is a demand for it – but the basic plug-in is, and will remain, free…

    Keep up the good work – I just LOVE this web site and the podcasts.

  2. For InDesign users on Mac OS X (Windows too maybe?), an alternative (maybe wrong but it may help a lot) is to turn the display mode from Colors to Grayscale in System Preferences > Universal Access.

  3. I see your point, Branislav, but that means you cannot use the File>Export feature for PDF. This plug-in makes it grayscale in both PDF and print (and on screen).

    Ultimately, the best way to do this is with Photoshop, of course.

  4. Or simply create a layer containing the flattened grayscale version within the RGB file. Then if you want a pic to be in grayscale, just go to Object > Object Layers Options…

    This is where I think that an Object Style could order all layers of imported Adobe files to be disabled and only the layer named “Grayscale” to be visible. Et voilà !

  5. Hi Branislav,

    Thanks for the comments – good points!

    However, another reason why some people asked us to create this plug-in is when they are creating a color publication, but want a few of the images to be printed in pure B&W – and leave the rest alone. And want to do it quick.

    An example I am ‘inventing’ on the spot here – maybe a magazine page with ads – some ads should be B&W, some color (and the customers pay different prices for each). If the customer delivers color images for a B&W ad, this plug-in is a quick and dirty way to print the B&W ad in pure B&W.

    And it’s easily scriptable – so workflow systems can use this as a much easier approach when automatically placing pictures into ads – “if ad = B&W set label to gray” – much quicker than scripting Photoshop to do the conversion.

    It’s not a panacea, and has severe limitations, but I do think there are for whom this is useful…

    Cheers,

    Kris

  6. Kris, I agree that it has severe limitations. For example, the fact that you can’t use transparency effects is pretty bad. I just noticed you also can’t colorize the grayscale image (normally, you can select the grayscale image with the Direct Selection tool and click on a color in the Swatches palete). Oh well.

    A suggestion, if I may: Given that both InDesign and Photoshop are scriptable with ExtendScript (javascript), perhaps you could add a second option to open the color image in Photoshop, convert to gray, then (as an option) save with a different name, and update in InDesign. I would love to see more automation between the Suite applications.

  7. Hi Dave,

    Just to let you know I’ve just uploaded a new and improved beta version (1.0.5) of Color2Gray. This one should remove the ‘transparency’ limitations, and resolve a few more bugs.

    So now you can colorize!

    Cheers,

    Kris

  8. For some reason, although the image displays as gray in my InDesign CS2 (Mac), it does not print in grayscale, that is to say, when I turn on separations in the print dialog. Interestingly, when I export as a PDF using a preset, such as the High Res preset, it saves it as a color image.

  9. Hi
    i only got to test your plug in just now as i was exploring your site.

    This plug in does wonders to our work flow.

    our company does a lot of typesetting of financial documents and annual reports and these contains pictures of directors of the company and among other things. We usually covert these images from photoshop and then place it to indesign which takes a lot of time since our jobs are always on arush basis. this cuts off a lot of time in coverting these images.

    Our boss is happy with the result.

    Thanks and more power

  10. Hey David, thanks for the nice review and thanks Kris for the plugin. I’m designing a photo album for a photographer, and I wanted to use the plugin to easily convert some of the images to b&w, only so I can see how it looks, and than do it photoshop, but I’m using InDesign CS3 and the plugin doesn’t work. I got it to appear in the menu, but when I press it nothing happens, not on the screen and not in print. Any ideas?

  11. I don’t think Color2Gray has been updated to CS3 yet. With all of Rorohiko’s plug-ins, make sure you have the most recent Active Page Item Runtime plug-in. Check with rorohiko.com for more info.

  12. Another option is to draw a white rectangle over the image, in ‘transparency’ set it from ‘normal’ to either ‘saturation’, ‘hue’ or ‘color’ and set ‘opacity’ to 100%.

  13. Hi Christoph,

    Cool trick; the effect is similar, but I wanted to point out there is one important difference: with this trick the ‘gray’ image will render on all plates, instead of just on the black plate, making it more like a ‘dark brown-and-white’ than ‘black-and-white’.

    You can see the difference between what Color2Gray does and what your trick does by doing a separations preview.

    Cheers,

    Kris

  14. Thanks for the quick fix for grayscale! I tried to read through the InDesign help to find out how to do this and was getting so lost.

    Thanks also for the original post and describing the transformation as “magic” – isn’t everything as important as this achieved by magic? LOL. :-)

  15. The plug-in doesn’t work for me. I select my object using the Direct Selection tool. I select “API > Force Render as Gray” from the context menu. But nothing happens; the image stays in color.

    Little help?

  16. Jeanna, make sure you have the most recent version, and make sure you’re attempting this on a bitmapped image, such as a TIFF or JPEG. It won’t work on AI or EPS or PDF files.

  17. I’ve worked with it and it’s great, it converts them to grayscale using only K (black) channel, so it’s perfect for one single (also spot) color press output.

  18. Hello,

    C’est vraiment dommage que ce raccourci très pratique de transformation d’une image couleur en noir et blanc sur Xpress n’ai pas été réalisé par Adobe pour Indesign.
    Naturellement des gadget sont possibles mais en natif cela serait plus stable
    Bravo pour vos travaux

  19. Just downloaded and awesome plugin.
    I was selecting groups of images to do in one hit.
    and it did..
    Although i found one every now and then didnt change.
    (im not sure why they are ALL jpgs).
    But it has saved me days of changing pictures.

  20. Hmmmm, what happened to the free version? Looks like this plugin has gone commercial with version 2.0. Does anyone know where to get the CS4 1.0.10 version (pre-commercial version)?

  21. Pingback: Prove » Blog Archive » convert pictures to grayscale

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