You photoshop experts

[stevehertz]

This scan of two tuning scale dials are reversed in preparation for printing on to clear sticker paper. However, a test print onto paper shows that the yellow cast (as result of the original scale having yellowed with age) is causing a problem. Basically I want a 'clean' black and 'clear' scan that I can print from. I've tried to remove the yellow cast using contrast and brightness but you can only do so much before the lettering itself starts to get affected. If I send the scan to someone who is adept at Photoshop, could they remove the yellow cast so that it prints just the black lettering please? Cheers.

NB, the image below is a screen grab (not the original hi res scan) for reference only.

[emeritus]

For this sort of thing, I use the "line art" option of my Epson scanner that produces pure black and white images directly.

On my Win 98 and XP computers, it is possible to change the attributes of an image file from colour to monochrome, thereby removing the colour information. 1 bit monochrome is an option.

[paulsherwin]

Can you just convert to monochrome, then increase the brightness and contrast to lose the light grey background? I don't use Photoshop so can't give detailed instructions.

[Panrock]

Something like this?

Steve

[bluepilot]

Personally I use GIMP. One way of doing it would be to select the colors>levels option. Then select the black dropper and click on what should be black then select the white dropper and click on what should be white.
You can also just convert the image to black and white by adjusting the corresponding threshold. You need a high res image for that or the edges can be a bit ragged.

[paulsherwin]

Exactly Steve. If the lettering starts to degrade it can easily be touched up pixel by pixel.

As Stuart suggests, there are lots of ways of achieving the result.

[wireman]

On the version of Photoshop I have, Image, Adjustments, Black and White, then boost yellow looks like it might be worth a go.

[Panrock]

On the low definition image above, I first converted to monochrome, then changed the brightness and contrast, applied a little gamma correction, and finally some coarse and fine sharpening. I use a twenty-year-old edition of Paintshop Pro.

Steve

It was a while ago that I did this, try the curves function, this lets you map any original value to another by wiggling a line. Instant feedback too.

[markfff]

Originally Posted by stevehertz

If I send the scan to someone who is adept at Photoshop, could they remove the yellow cast so that it prints just the black lettering please? Cheers.

Sure I can do it. How big is the file, will it go by email? I have gmail, so less than 25mb I think