Optical brightener

[Photo Engineer]

The statement referred (I think) to the changes in color of the silver image due to antifoggants. This is used in B&W prints, of course, to get the image tone desired.

PE

 

[newcan1]

The statement referred (I think) to the changes in color of the silver image due to antifoggants. This is used in B&W prints, of course, to get the image tone desired.

PE

Agreed. I was merely taking issue with the statement after that, to the effect that, as image silver is removed, BZT should not have much effect. My experience is that it can have very beneficial effect. While the image silver (the color of which is influenced by BZT) is removed in the RA process, that is not really the point. The point is that BZT restrains fog development, so that where the fog does not appear, the color dyes associated with the fog are also not created. Without BZT, the silver fog gives rise to an associated dye that is left behind (in my experience, the yellowish color that the paper takes on). By restraining the fog, the associated dye is also restrained. I have brought back to life many slightly fogged color papers this way, restoring them to bright whites - in particular Ektacolor Edge and Fuji Crystal Archive C..

 

[Rudeofus]

It has as of yet not been clarified, whether the yellow image tone the OP complained about was a result of fogging or of paper base discoloration. Since the discussion wandered along the "paper base discoloration from old optical brightener" trail, I thought the question regarding BTAZ referred to the bluish image tone it creates in B&W processing. Obviously BTAZ will have plenty effect as antifoggant.

 

[pentaxuser]

I thought I was beginning to understand this issue but I am confused as ever. Can I ask 2 simple questions:

1. If it is age-fogging, as may be the case with 20yr old RA4 paper, can benzotriazole reduce the creamy-yellowish borders?
2. Are there optical brighteners in RA4 paper of 20 year vintage that will produce the yellow effect and will the application of an proprietary optical brightener resolve this issue or is the yellow border effect caused by something else in old paper that cannot be cured by any means whatsoever.

I have got to the stage of "I must get to the bottom of this if it kills me". Would it help if the OP were to contribute to this discussion? I think so but I don't know

Someone please answer my questions soon. I need to go to bed now as it is very late in the U.K. I hope that I can rely on my sanity lasting another 24 hrs but I cannot guarantee it.

pentaxuser

 

[Photo Engineer]

Answers to all is "MAYBE".

PE