Re: Was Re: question on sizing, now fish eyes
Just a couple thoughts: I think as in all things gum there are a number of different answers to this question and more than one answer can equate to a contributing factor. In other words, some get fisheyes on unsized paper with gum but not on unsized paper with casein. Some get fisheyes with gum with certain pigments more often than others on sized papers. In Katharine's experiment, below, where the coating "opens up" on Yupo, this is the fisheye that I am referring to. It is sort of like when you are making bread dough and it will not "relax" and so you leave it for a moment to let the yeast work in it and soften its tendency to spread out into pizza crust or whatnot. Otherwise the bread dough keeps retracting and doing these little tearing/separating things on the surface. My guess is it relates back to the viscidity discussion we had years ago in that at a certain point of too much or too little even (!) water, the coating is unable to hold together and retracts, and this ability to not hold together can be exacerbated by sizing or pigment qualities or pigment additions or whatnot. But sizing in no way is the main nor only issue because I always size and I only occasionally get fisheyes---with magenta---whether first or last coat. A test if I had time would be to use unsized and sized and coat side by side same mix ratio of yellow and magenta and see if one could reproduce consistent results. But Henry, you are right in that generally they can be worked and brushed out, in my experience as well. Chris __________________ Christina Z. Anderson http://christinaZanderson.com/ __________________ ----- Original Message ----- From: "Henry Rattle" <henry.rattle@ntlworld.com> To: <alt-photo-process-l@usask.ca> Sent: Wednesday, September 10, 2008 12:04 PM Subject: Re: Was Re: question on sizing, now fish eyes On fisheyes - I get them from time to time and have always put them down to some inconsistency in the sizing (brush-coated 3% gelatine with formaldehyde hardener). They always brush out once the gum-pigment layer begins to get a bit more viscous, and as far as I can see have no effect on the final image. Henry On 10/9/08 18:28, "Katharine Thayer" <kthayer@pacifier.com> wrote:Laura, I can't find the other thread you referred to so maybe it was under a title that wouldn't identify it as being about a coating problem with Payne's grey. However, since "Payne's grey" isn't a pigment in and of itself, but is simply a convenience mixture of some blue (different manufacturers use different blues) and lamp black, it's unlikely that it would behave in some way that would be linkable to the color name "Payne's grey." When I got your post, I thought "good timing," because I've been planning to get back to my troubleshooting page, which I've been promising for a couple of years. So I went downstairs even before I'd had my shower, to make fisheyes to show you. But as I said, I seldom encounter fisheyes, so it wasn't such a simple job to make them happen. The "fisheyes" I occasionally get (on Arches bright white sized with gelatin-glyoxal) are very small, almost like pinpricks, so maybe they really don't qualify as fisheyes, except that they appear in the same way as larger fisheyes, as a visible lateral retraction of the emulsion from areas of the paper. Anyway, this morning I couldn't make that happen on Arches bright white, so I pulled a piece out of my stack of different kinds of paper sized with different stuff; this one happened to be Lana sized with gelatin and glutaraldehyde, and got the kind of fisheyes I'm talking about; I've scanned that for you. I also tried to make the bigger kind of fisheyes, the ones that open up to 1/4" or 1/2" wide and really look like fisheyes, by coating on Yupo, but was unsuccessful until I added a little water to the mix, and then got some of these fisheyes. I took a picture of this with my cheap digital point and shoot; it's blurry but I hope you can make it out. I'd be interested to know if people mean one or the other, or something different, when they refer to "fisheyes." In both cases I left the fisheyes as they first appeared rather than attempting to brush them out, so as to not obscure what they look like in their undisturbed manifestation. http://www.pacifier.com/~kthayer/html/fisheyes.html That page is temporary, just uploaded for sake of this particular discussion. Katharine On Sep 10, 2008, at 3:01 AM, Laura Valentino wrote:Does anyone have a scan of this "fisheye" effect they could share? A couple of weeks ago I wrote about a "bubbling" with payne's gray, so I also wondered if it was something related to the pigment. Or it could've been because it was a different brand of paint, because that was the only variable that changed from the other colors I was trying. I washed the layer all away (after learning here I could do that) so I can't share the effect I got. Laura zphoto@montana.net wrote:Also, because I get it consistently with magenta and not yellow I think it must have some relation with the coating but maybe not the gum, maybe the pigment or who knows. I'll watch it for a while and see if I can determine any other factor that might play into it.
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