Mass conversion colour to mono images

[hannesrempel]

On the "PDF-XChange products comparison chart" I found this:

Graphics Downsampling options (Linear, Bilinear, Bicubic) also Colour -> Grayscale -> Mono options

This should be possible with PDF-Tools.

Also I found the following quote from here: viewtopic.php?t=3804&p=16983#p16983

PDF-Tools will allow you to reduce image files by downsampling and conversion of image fiiles from full colour to grayscale/mono

Now, my question is: How can I convert images from colour to mono?
I would expect that I con do this with "Save as Optimized" (PDF-XChange Editor) respectively "Optimize PDF" (PDF-Tools). But I cannot found this option.
I found this option in the editor only for a single image: open the content pane, expand the content of a page, open context menu with right click on an image, choose option "Recompress image..."
My challenge is to change 600 images in my document and I am not willing to compress all 600 images one by one.
Therefore I have selectet all images and tried to compress all at once. But when I select more than one image the option "Recompress image..." is no longer displayed.
What can I do?

[Will - Tracker Supp]

Hi hannesrempel,

Thanks for the post - Unfortunately that post is a little misleading and is only for when converting image files to PDF, rather than optimizing an existing PDF.

For now, neither Tools nor the Editor can do this en masse without printing. We've added a feature request for consideration in a future release of Tools (possibly the Editor too), as myself and my colleagues agree it's a great idea. Ultimately it's up to the Dev. Team, so we can't guarantee it just yet. The FR ticket number is RT-4415.

For now, I'm afraid the only option would be to print to PDF via the Editor (e.g. printing with Editor to our XChange Lite or Standard printer), and select the following under Advanced Print Options:


Cheers,

[hannesrempel]

Hi Will,
thank you very much for the request.

We've added a feature request for consideration in a future release of Tools (possibly the Editor too), as myself and my colleagues agree it's a great idea.

[Dimitar - Tracker Supp]

[hannesrempel]

The FR ticket number is RT-4415

Hi Will,
Is there an update für ticket RT-4415?

[Tracker Supp-Stefan]

Hello hannesrempel,

A work item has been created in our internal system and it will be worked on soon, but that's all the updated info that I have for now!

Regards,
Stefan

[hannesrempel]

A work item has been created in our internal system and it will be worked on soon, but that's all the updated info that I have for now!

Hello Support-Team,
Is it already possible to convert many color images to grayscale?
Or can you please tell us how long it will take until the Bulk Recompress Images toolset is finished?
Many thanks!

[DenisO]

Hi hannesrempel,
you can try Convert Colors tool. Just select Object type image and gray gamma profile.

[hannesrempel]

Hi hannesrempel,
you can try Convert Colors tool. Just select Object type image and gray gamma profile.

Hi DenisO,
I have now tested the function and it is well thought out.
But now I have a question about ICC profiles.
In case of scanned pages (especially with yellowed pages) the profile "Gray Gamma 2.2" creates a very dark background. It is much darker as if I use the recompress image tool to convert to grayscale. (Please see attachements).
Do you know a ICC profile that works better for scanned texts?
It would be nice to have that.

[dave.kracht]

The FR ticket number is RT-4415

Hi Will,
Is there an update für ticket RT-4415?

Same question after 1.5y. Any progress? Btw. are the tickets (like 4415) available for the public somewhere ?

[TrackerSupp-Daniel]

Hi, dave.kracht

There has been no new progress on this as of yet due to our recent focus on implementing better accessibility functionality for version 9. Regarding tickets, it is an internal only system, so there is no way for you to look up a ticket beyond asking a support team member for an update on the ticket number here or via email.

Kind regards,