Pen Blend mode that works well on bright, dark, and in between darkness

[Zarquan314]

I use PDF XChange Editor's to grade papers. I the annotation tool to hand write notes on student's digital papers. But I have a bit of a problem where sometimes the penstrokes can be hard to read. This is because some students use a white background, some a black background, some students hand write their homework and take a picture, which results in varying ranges of darkness, which effects the readability of my comments.

I don't know that much about color terminology. I've tried a few settings, and some are better on some backgrounds but terrible on others. Is there a good blend mode that will make my text readable/has good contrast with whatever background I am writing on that doesn't make my pen a so I can set it and forget it?

[Daniel - PDF-XChange]

Hello, Zarquan314

If you use a white pen color, and set the blend mode to "difference", you should get this effect:

image.png

image(1).png

image(2).png

Kind regards,

[Zarquan314]

Since I'm grading, I would like my pen to be recognizably a shade of red so students can distinguish between my writing and theirs. If I set it to the opposite of red and use difference, it becomes red unless I am writing on black, which is OK, but not perfect. The issue is that on some darker photos of paper, it can still be very hard to see.

Currently, I use normal for very bright and very dark settings and multiply for in the middle. Fortunately, no student uses a red background, so this works for me except for the repeated settings changes.

Keep in mind that I don't consider this a pressing problem, as it isn't hard to switch between the settings. It would just be nice to not have to think about it.

[Daniel - PDF-XChange]

Hello, Zarquan314

I am afraid that, aside from the difference blend mode, none of the others offer an appearance that is reliably contrasting and would appear visible in various locations. I would maybe suggest using the "normal" blend mode, and setting it to a vibrant red color (open the color palette, set R to 255, and the others to 0):

image.png

As that should give this effect (The forums seem to dislike this image and will not show a preview for some reason, click to view):

image(1).png

As you can see I drew 3 lines this time, each with a higher line "weight/width" the bottommost line is 3pt width, which helps to make it stand out a bit more in the darker grey, despite the minimal contrast.

image(2).png

Kind regards,

[Zarquan314]

Ok, I'll just keep doing what I'm doing then. It would have been nice if there was a magic solution that works well everywhere, but that is a lot to hope for.

[Stefan - PDF-XChange]