Photoshop / GIMP experts sought!

[Chris Wilson]

PDF images of a PCB, to size, spot on. The black is the traces, mirrored. But when I, or a pro print shop, print to clear film or heavy tracing paper the image of the traces is not a dense black. If I do a Print Screen of the page 4 of the files that I want to use, and open in Windows Paint, and then draw a black line across a blown up pad, it seems obvious to me that the PDF is not true dead black.

See http://www.gatesgarth.com/not-dead-black.png

Can it be altered in something like GIMP of Photoshop to make all traces dead black without losing any edge definition of the traces and keeping the images the exact same size?


As say, page 4 is the only one of relevance to my needs, thanks.

PDF's at http://www.gatesgarth.com/traces.pdf

(page 4) Thanks!

 

[TheAlex]

There will be a few ways of doing it. The first that comes to mind is to use a Levels adjustment (in Photoshop, GIMP and others). Drag the left arrow beneath the histogram to the right, until those blacks become as black as they can be (you can tell by sampling the colour - all RGB or Hex values will be 0). If you go too far, it might mess up the edge definition.

 

[Chaos]

If this is to make your own pcb, I mind reading in the past a lot of folk getting problems printing dead black prints onto transparency.

I mind someone said they had good success with a cheap Canon Pixma printer with black pigment dye ink.

Farnell also sell film for pcb prints but not sure if it will be worth it -

http://uk.farnell.com/mega/100062/l...ey=http:en-GB/Element14_United_Kingdom/search

 

[Chris Wilson]

Hi TheAlex and Chaos, thanks for the replies, yes it's to make replacements for three tired PCB's in an obsolete power supply. I will try the adjustment TheAlex talks of. I have the film Chaos mentions, but on this the image is also from from opaque, I am convinced it's a facet of the PDF images as I have not had this issue before, using other images that appear dead black. Thanks.

 

[Steeps]

I've opened it up in illustrator as it's a vector drawing, the pcb drawings are black according to cmyk, it might be that paint etc are using a richer black that is used for printing where parts of cyan/magenta/yellow are added to give it a deeper colour. I'll upload page 4 with them in rich black instead of cmyk black.

Here's the link to page 4 with it converted to rich black (C:50% M:50% Y:25% K:100%)
http://steeps.net/steeps/ocuk/misc/page4.pdf

 

[gord]

I've opened it up in illustrator as it's a vector drawing, the pcb drawings are black according to cmyk, it might be that paint etc are using a richer black that is used for printing where parts of cyan/magenta/yellow are added to give it a deeper colour. I'll upload page 4 with them in rich black instead of cmyk black.

Here's the link to page 4 with it converted to rich black (C:50% M:50% Y:25% K:100%)
http://steeps.net/steeps/ocuk/misc/page4.pdf

Pretty much this. Paint doesn't support the CMYK colour model so print screening the PDF and dropping that in will always be different.

Here's page 4 converted to RGB. https://we.tl/wBozymy5Du

 

[Chris Wilson]

Thanks to all, the conversions are excellent and a big improvement can be seen in the printed quality, the density increase is very apparent. Your time and trouble is much appreciated, thanks again!