Paul C. Buff, Inc. Technical Forum

Several years ago I got the BusyBee package which included the large 30X60 softbox along with umbrellas, stands, 4 B800s, etc. Its been a very good package and I am still using it today with additional tools I've added over the years.

The other day I used the original 30X60 softbox along with another B800 bouncing into a white umbrella. One was on each side of the model and I used equal output settings (measured by a light meter). The background was white paper and not seperately lit.

When I processed the photos, I noticed a distinct shift in color balance between the left side (lit with the softbox) and the right side (lit by the bounced light). The side being lit from the softbox was noticably more yellow. This made me wonder, since I had not run across this before (although I hadn't tried to evenly light in this way)... can the white diffusing material used in the older softbox yellow with age and cause this color shift?

The light output on each side was equal but the color balance was different. If the softbox, which is several years old, is causing this, is there a replacement front diffusion material available?

Diffusion fabrics can yellow with exposure to contaminates in the air - particularly smoke. Softbox diffusers can be machine washed and even bleached. This should help if they have yellowed. But don't use detergents that claim to have "brighteners"

There is also a situation that fabric vendors tend not to be consistent in the exact color balance of their fabrics. Most white nylons, if untreated, tend to lower color temperature by about 200°K. Fabrics with UV brighteners can raise color temperatures dramatically. I have bought many umbrellas, softboxes and diffusers from many manufacturers and have never seen one that is actually neutral . . . most are warm by about 200° but many with brighteners can be cold by as much as 600°K

It's possible your umbrella has UV brighteners - there was a rash of these from most sources a couple of years back.

There can be similar, but less severe, differences in aluminum reflectors depending on the degree of brightness of the finish (achieved by "bright dipping" a chemical process.)

We have been paying particular attention to this recently, but it is rare to find two different modifier types that don't have some degree of color difference - from any supplier.

Thanks... you're advice is very much appreciated. Both softbox and umbrella are "Bee" brand but the softbox is older but never exposed to smoke. I'll try washing the softbox and see if it helps.

Picked up a used Plume Wafter w/ a pretty yellowed front diffuser. Washing w/ detergent and even soaking in a bleach solution (one cap for a gallon) didn't change it at all. The front diffusers are meant to be replaceable for a reason...