Need to darken CAL files

[mrjacoby1]

I'm receiving blueprints from a customer in .CAL format. I need to convert to PDF. However, the files are coming in EXTREMELY light and hard to read. IS there a way to "darken" them up prior to converting to PDF? I've already tried adjusting the DPI from 72 to 200 to 600 to 1200 (via Image > Set DPI ). No help.

The attached image shows the file info that appears in the lower left corner of my XnView session regarding this file. Thanks.

[mrjacoby1]

Also, in the picture I've attached, you can see (in the upper right corner) how light the text on my CAL file is.

[XnTriq]

Last year's suggestions didn't work for you?
Could you upload a sample file as an attachment (7-zip/RAR/ZIP)?

[cday]

I'm receiving blueprints from a customer in .CAL format. I need to convert to PDF. However, the files are coming in EXTREMELY light and hard to read. IS there a way to "darken" them up prior to converting to PDF? ...

Weren't we looking at the same issue around a year ago:

Re: Is it possible to make converted files darker than origi

I've been able to darken the relevant part of the image you posted [although the DPI is too low to be useable] but that file was a JPEG so the adjustments I used can't be applied directly to CAL images, which are 1-bit black and white. You might look at the above thread anyway, though.

I think that the issue is most likely the large pixel dimensions of the CAL CAD files when opened at a suitable DPI, which as mentioned in the above thread can make them unreadable on a normal monitor unless you zoom well-in; one of the latest '4K' monitors would likely render them rather better but would be an expensive test if you have to obtain one specially, and would likely still not really provide a full solution.

Another possibility might be to get the files printed, if necessary by a specialist print house, if that form of output would be useable.

Ideally you would upload a sample file, but if they are proprietary I realise that that isn't an option.

Possibly the forum librarian can add something?

[cday]

Possibly the forum librarian can add something?

I see he already has!

In summary, I don't think your files need enhancement as the images are already black and white: you either need to zoom well-in or use a viewing method that is more suitable for the pixel dimensions of the images.

[mrjacoby1]

Somehow, I missed those suggestions from last year. Thank you. It seems to have worked.