Can I touch up a film positive with a sharpie?

[newbiescreenprinter]

Hi there,
I would like to add a bit more trapping to a bottom layer of color. Instead of having another film positive made, could I just take a sharpie and draw an outline around those shapes? I don't need it to expose razor sharp or anything. Just give me a 1/8 inch more to my shape.
What do you think?

[Iron Canvas Studios]

I've done it before. I've also used my brush pen and that works even better.

[judge]

Sharpie has never worked for me. Steve Walters always reminds me which pens seem to work best. PM steve.

[El Roacho]

i use fine tip paint pens. try a test spot on your positive, if you cant see through it, go bananas.

[NeroInferno]

One of the best mark for film is KIMOTO PAKE

[hartman]

Sharpie makes a paint pen which works just fine but a regular sharpie likely won't do it.

[caribou]

i've used a brush and india ink to great success.

[steve w]

paint markers, Ident-i-pens, most anything that's labeled "opaque, permanent, and waterproof"
regular sharpies are transparent and will wipe off of film

[ASPrintingPress]

Yup, I've always used Staedtler Permanent Lumocolor

[squeegeethree]

Koh-i-noor 3071F acetate ink

Also I second this.
"One of the best mark for film is KIMOTO PAKE"