Re: tonal inversion and pigment loads

Katharine,

Right now I'm interested and trying to understand the effect we call
inversion. I acknowledge (and sometimes experience) other types of
stain, they are certainly also interesting and deserve further study but
my time is not infinite. Also, I have a life outside of gum dichromate.

The net result of all this effects is to put pigment in the wrong place,
as you say. True. However, this fact doesn't help me or anybody to
understand why and under what circumstances inversion occurs.

If you want to define inversion as a special case of pigment stain, be
my guest. I'm not too interested in definitions at this stage, to tell
you the truth, since I consider that the facts have not been firmly
established yet. In my opinion we need more time and more observations.
This is what I am making, when I have time: observations.

Two months ago, when Joe Smigiel started this thread with his
observation about inversion, you said in a post that you had never seen
this effect. Sixty days later including holidays you have a definition
written in stone, or at least in a web page. Amazing, to say the least...

Tom Sobota
Madrid, Spain

Katharine Thayer wrote:
> Tom,
> I think our difficulties arise largely from the different ways we
> define things. I spent some time a while back rethinking my definition
> of pigment stain, and in fact did a lot of my thinking about this in
> public; the result of these ruminations can be found in the revised
> pigment stain page I announced yesterday. I now define pigment stain
> as pigment deposited where it doesn't belong, and I define tonal
> inversion as a special case of pigment stain. . If you don't share
> my views on this, and if we are going to try to talk about this using
> completely different definiitions for pigment stain, then we're just
> going to go around and around in circles.
>
> On Jan 27, 2006, at 1:09 PM, Tom Sobota wrote:
>>
>>
>> In every example of inversion that I have seen, there are three regions:
>> 1. A first region corresponding to what we could call the shadows in
>> the negative. Speaking in terms of step tablets, the lower numbered
>> zones. In this region everything happens as expected.
>>
>> 2. A second region where the density of the negative (or step tablet)
>> is such that it doesn't produce any density on the gum positive. This
>> region is actually an extension of the first. It should go until the
>> darkest zones of the negative or tablet, and in general it does,
>> except that but sometimes it doesn't, when there's inversion.
>>
>> 3. A third region where the inversion happens, when it happens. In
>> this region the density is in general lower than in region 1, and in
>> some cases a few steps are differentiated. In other cases, as my
>> examples on glass, no steps are visible.
>
> But in all of these cases, it's pigment being deposited where it
> doesn't belong, which is what I call stain. It can be indelible or
> not indelible, and it can be lighter in tone where it deposits on top
> of a gum resist which repels it, but in every case, it's pigment in
> the wrong place, call it what you will.
>
> Katharine
>
Received on Fri Jan 27 20:26:04 2006