Color balance for pinhole

[ReFried]

Hello!
I just started using color-paper negatives in my pinhole camera. The most neutrally colored positive I could make from my first negative was cyan in the center encircled by a deep red. I then put a piece of a processed, but content-less, color negative in front of the lens. The most neutral positive I could make from this negative was a very pale lilac; there was no range of color in the whole image. I'm wondering if anyone knows how to correct for this problem so that I can have a nearly normal color range in the image??

Also, for my negative I used Fugi paper, there is a ton of writing on the back of it though. Does anyone know of a paper brand that has no writing on the back?

Thanks for any and all help!!

 

[keithwms]

Colour is not a strong suit of pinhole in general because the effective focal length for a pinhole system is wavelength dependent. In other words, the focus for redder is different from the focus for bluer light, and offhand I'd guess that the more off-axis (i.e. off center in the image) you go, the worse effect this would have on overall colour rendition and sharpness. Hence I would expect intrinsic radial colour oddities. Don't quote me on this, this is just the very first thing that comes to mind This is the reason why the sharpest pinhole shots are also the most limited in wavelength range- if you use ortho film or paper you then can get pretty good results because the effect is minimized.

On the other hand I have seen colour pinhole shots that were acceptable, so can you give some more details or post the example? How thick is your pinhole material, what's the size of the hole, etc.... what format are you shooting?

If you do a b&w shot what do you get? Over what radius do you see even exposure?

 

[Murray@uptowngallery]

I don't have a direct answer, but am wondering if with the processed negative as a filter you still had a different color at the outer border or if the pale lilac was fairly uniform.

If you have different colors in the center than at the outside either way, I would then ask if you have a fairly short, wide angle camera geometry which would tend to exhibit more exposure variation due to the notorious 'cos^2 falloff'.

If so, I'd suggest that with a longer camera (f.l. = negative diagonal or longer), the exposure across the entire frame will show less variation due to using a smaller central portion of the image circle.

If my hunch is totally off, I'll sit back & let someone else whose done it with color paper respond.

(composed while Keith was composing his reply)