Washing out optical brighteners in fibre based paper

[Todd Barlow]

I have read a number of warnings about excessive print washing causing the optical brighteners to be washed out of fibre based paper.

Based on your experience and or knowledge how long do you consider to be excessive washing times that would impact the optical brighteners?

I know the answer will depend on many variables, however I am only looking for a rough guide. I am using Ilford MGIV Fibre Based Glossy paper and a holding bath and vertical washer at 20 degrees C.

Thanks

Todd

 

[John Simmons]

With MGIV Fiber I have found that prints can be left overnight in a print washer without any noticible changes. Ilfords warmtone version is a different story.

Regards,
John

 

[foto-r3]

Optical brighteners will cause fading over time. Have you considered using paper that doesn't contain them? Just a thought.

 

[Muihlinn]

It's hard to wash out the baryta layer without absolutelly ruining the print, and that's what will give a pure white background and it's a major player on the apparent brightness; on the other hand the gelatin can take a bit of colour depending on a number of circumstances and that's what makes techniques like tinting with tea possible. MGIV is very tolerant to extended washing times.