Image to grayscale

[Chiefs420]

Win XP
Acrobat 9 Pro
Pitstop Pro 8.5

How do I change a CMYK pic in a pdf to grayscale while leaving the rest of the pdf CMYK? Seems like it should be easy, but I'm an idiot soooo......

[mattbeals]

Select the image and use the inspector window to convert to gray. Or did you want an action to do this?

[Sev]

Or use the Acrobat TouchUp Object tool. Right-Click on the image, and select Edit Image. This will open it up in PhotoShop, and you can convert it to grayscale in PhotoShop, as long as you have PhotoShop set up as your image editor, in Acrobat preferences.

-Sev

[Stephen Marsh]

Or use the Acrobat TouchUp Object tool. Right-Click on the image, and select Edit Image. This will open it up in PhotoShop, and you can convert it to grayscale in PhotoShop, as long as you have PhotoShop set up as your image editor, in Acrobat preferences.

-Sev

I personally would prefer the Photoshop route as I could control the mix to gray, rather than leaving it to a default algorithm which may lead to poor monotone reproduction when compared to the choices of a human (as an algorithm has no idea of image content, context etc).


Stephen Marsh

[mattbeals]

The intelligence of something like Elpical Claro is pretty sophisticated and yields very good results.

[Stephen Marsh]

The intelligence of something like Elpical Claro is pretty sophisticated and yields very good results.

I am sure that what it does it does well, as far as it goes with easy things such as setting tonal range etc.

That being said, I am sceptical Matt, when it comes to making monotones from full colour images - the software has no idea about actual image content from this particular perspective, not even two operators would make the same judgement calls when giving priority to differing hues at differing luminance ranges and saturations and how they "should" or "could" be represented in gray.

I am happy to be proved wrong, I can supply a test file if needed. I will be upfront and say that the test file would be stacked against even a "sophisticated" computer algorithm.


Stephen Marsh

[mattbeals]

It's the 80/20 rule Stephen, not 100% correct decisions. But if you want to see some files I'd be happy to do process a few. And by no means is Claro's decision the optimal parameters for the images. Some users simply use them as base/first round corrections. For many others the results are quite satisfactory for printing.

Again, anything automated is 80/20. Anyone who tells you different is full of shit. If you really want to evaluate it you need a broad range of sample files.

[bprint_tampabay]

I would vote for Matt's solution if there were multiple images that needed converting, and time was a factor.

But why would you want to give up total control via Photoshop if there were only a few images that needed conversion?

I'm pretty sure that I could create a better greyscale image than any automated software package, no matter how sophisticated.

[mattbeals]

I'm sure you could given enough time. That doesn't mean you are slow! No tool is going to replace a human. What the tool can do is make it easier for the human. All the changes Claro makes can be previewed in PhotoShop first. If you like what Claro did you can pass it along. If you think it needs additional tweaks by hand you can do that and then pass it along. If you don't like what Claro did then you can discard Claro's version and manipulate the image your self and then pass it along and Claro will return the image back to the PDF (in this case). You as a human still have the final say.