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M
mansourbakhtomid@gmail.com
Participating Frequently
August 3, 2020
Question

Image Mask

  • August 3, 2020
  • 3 replies
  • 2812 views

Hello, I have many pdf files created from tiff files of scanned technical drawings which tiffs treat as what so-called an "Image Mask" in them when we analyze them with acrobat Preflight tool, now I want to know what an Image Mask is? How can I make a tiff treat as an Image Mask when it is converted to pdf in a simple way or with a tiny add-on or .exe software?

Thanks and Regards,

Omid Mansourbakht

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3 replies

T
Test Screen Name
Legend
August 11, 2020

An image mask is a special kind of image

Normal images:

- ignore the last colour used

- every pixel is opaque (unless transparency is applied separately)

- every pixel has a colour

- has a colour space (such as greyscale or RGB)

- has 1,2,4,8 or 16 bit data for each pixel

An imagemask

- use only the last colour used

- each pixel has either a colour or is transparent

- pixels do not have a colour, they are visible or transparent (on or off)

- have no colour space

- have always 1-bit pixels

 

How does an image mask compare to a 1-bit greyscale image?

- the image mask takes any single colour; pixels are that colour or transparent

- the 1-bit greyscale image will produce either black or white, never transparent

 

Image masks are often used for bitmap fonts.

M
mansourbakhtomid@gmail.comAuthor
Participating Frequently
August 11, 2020

Hi ls_rbls,

Hello and thanks for the reply, but my purpose is tiffs which treat as the thing so-called "Image Mask" in pdf, not clipping mask.

ls_rbls
Community Expert
ls_rblsCommunity Expert
Community Expert
August 11, 2020

Well, with my current knowledge of Acrobat, I think that the confusion is on how we're interpreting the concept of layering masks, which is done with image manipulation programs and photo editors. 

 

In Acrobat the concept may appear to be similar in the sense of how PDF layers are used.  But as I mentioned earlier Acrobat is a PDF editor, not an image editor.

 

As a PDF editor,  image files in Acrobat  (regardless if they were clipped,  masked or not by other producing software) need to be converted to PDF.   Then the PDF editing would involve layering; which I believe it is referred to PDF layering (not image masking; key detail since the image file has to be converted to a PDF first).

 

I think that is what you're referring to.

 

Is that is what you were referring to  then look at  this other guidance:

 

https://helpx.adobe.com/acrobat/using/pdf-layers.html

 

M
mansourbakhtomid@gmail.comAuthor
Participating Frequently
August 22, 2020

Why do you WANT to do this particular thing? Please be detailed about your motivation. What is wrong with the conversions you have? What image representation have the TIFF files? If you are not an experienced programmer, poking in github for sources isn't so likely to be productive.


Thanks for your reply, my motivation is to know what the differences between two conversion are (normal conversion in comparison to unusual conversion) and then apply the latter if has some benefits; by the way I am seeking a way to do that. (I am not a programmer and do not have any skills in programming).

Thanks and Regards.

ls_rbls
Community Expert
ls_rblsCommunity Expert
Community Expert
August 3, 2020

I've read quite a few times here in the forums that Acrobat is not an image editing software. As such , image masks are no really supported in Acrobat.

 

From reading a bit more, I 'v e learn that when a document that was produced with another applicatiom, and it contains image masks when it is exported to a PDF file, what most people do is optimize the PDF to remove certain objects, and in other instances flatten the PDF and/or reduce the file.

 

See what Acrobat can handle as far as images is concerned here: https://helpx.adobe.com/acrobat/using/edit-images-or-objects-pdf.html

 

Additionally see these two other discussion: 

 

 

 

To really work with masks you need a product like Adobe Photoshop , for example. 

 

But to answer your question  a mask is defined in this excellent Adobe Photoshop quick tutorial with practice examples: https://helpx.adobe.com/photoshop/how-to/layer-mask.html

 

More practical explanations here: https://helpx.adobe.com/photoshop/using/masking-layers.html

 

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