do some films retard UV light?

[kentrush]

Dear All,

I'm new here so hope I'm doing this right. Do any of you know if some films contain something (a dye?) that retards UV light. I print collotypes and I had no problem when I was using Efke 100 11x14. But now that I am using Ilford FP5+ I am having trouble getting the contrast I need in my printing plates. Thanks for any help.

Kent

[Willie]

Have been told that TMax100 does. Not sure about the others.

[Pere Casals]

FP4+ or HP5+ ???

Kodak TMax 100 (TMX) blocks UV a lot, IMHO this does not happen with TMY, HP5 or FP4

You can acquire a UV meter for your smartphone, like the $25

https://www.amazon.com/Checker-Ultraviolet-Smartphone-Android-iPhone/dp/B01917YSX2/ref=pd_lpo_sbs_469_t_0?_encoding=UTF8&psc=1&refRID=VBGFJQH5MH1JD7SYDSFC

174453

In this way you can measure UV intensity before and after the light goes across the film, so you can calculate the UV opacity of any film base.

Regards

[koraks]

Tmax 100 is indeed a UV blocker holding back 3-4 stops of uv, but only the sheet film does this. It's the only film I'm aware of that significantly blocks UV. However, with greatly increased exposure times, it can yield normal contrast in alt process prints.

If you are having a contrast issue, development is more likely the issue. Both fp4+ and hp5+ can easily be developed for high-contrast alt process printing.

[Jac@stafford.net]

Great question!

It is not clear to me if you are asking if blocking occurs in taking the photo or after, during printing.

[Vaughn]

Hard to build up a lot of contrast on HP5+...FP4+ is much better for that. Otherwise, perhaps HP5+ in a pyro developer might do the trick.

TMax100 sheet film has a UV blocking layer...only one I know of.

That said, I have 100 sheets of 11x14 HP5+ that I will want to kick up to a DR of around 3 or so -- picking scenes with a large scene brightness ratio to start with will be the key...and the sort of light I want to work with.

[kentrush]

Have been told that TMax100 does. Not sure about the others.

Thanks for that. I'm going to do a test where I expose a negative that I know works well alongside one of my Iford FP5+ negatives and see if they produce different contrasts.

Kent Rush

[kentrush]

Thank very much, I'll try the app!

[kentrush]

Thank you!

[kentrush]

During printing and thanks!

[kentrush]

Thank you and good luck with your film!

[SMBooth]

Pyro type developers have a stain which blocks UV.