[alt-photo] Re: Tea toned cyanotype

[Loris Medici]

Alberto, if they bleach the image before toning, and if there's some
gallate / tannate compounds in the toner, then we can assume some
toning is taking place indeed. But I'm not sure if that can be proven
/ disproven by testing with the method outlined below. I agree that
most of the images put in tea or coffee without bleaching in the first
place, are mostly changed due staining of the paper base, since the
paper is changed, the perception of the image is changed along with
the paper. I wouldn't count that as "toning", that would be (in
agreement with you) just staining...

Regards,
Loris.


2012/12/15 Alberto Novo <alt.list at albertonovo.it>:
> Lately, the cyanotype toning with tea or coffee is becoming a real fashion.
> I am puzzled because it seems to me that most of what is perceived as color
> change may be just staining.
> I tried to download some pictures from internet and change the white point
> by selecting it from the paper outside the image.
> The result is that most of them return blue.
> Do you think that this check may be assumed as a good indicator of the
> effectiveness of toning?