[alt-photo] Re: no shrink, no size tricolor gums

[Trevor Cunningham]

  My cyanotypes are pretty consistent at around 4.5 minutes. If the 
water is alkalai, wouldn't that bleach, or challenge a cyanotype's 
development? I could very well be slathering on the coating too heavy.

On 9/14/10 7:27 PM, Charles Ryberg wrote:
> Trevor--I know it is impossible to judge UV strength by eye, but a 
> minute or even two in bright sun seems long to me.  What is your 
> cyanotype exposure time?  I find gum to be about .3 to .5 what cyano is.
>
> Flaking off is supposed to be caused by too thick a coating or alkali 
> in the wash water.  Can you test your water?
>
> Good luck    Charles   Portland Oregon
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