Something I want to also address is the dichromate part of this process. The original method of gum printing used a bichromate as the sensitizer. For the past century, or so, dichromate has replaced this, being faster than the original form of bichromate. There are two base forms of dichromate; ammonia dichromate and potassium dichromate. I have always used the latter form, although the former is a bit faster, more light sensitive, than the former. Both can be bought today. The dichromate solution I use is 13%, which is saturated at that point. The ammonium dichromate is mixed to 25%, hence, more sensitive.
The obstacle to overcome in this print image is the window area, which is about three to four full stops beyond the foreground, in any photographic medium that a good amount to deal with in printing. There were two avenues open to me to bridge the two areas for further printing. The first one was a second layer of lamp black just in the now nearly blank white area where the window area is. One drawback to that direction is perfectly laying on the gum without crossing any of the visible areas of the image, which would then create a black line after printing.
I chose the second avenue that arrived just moments after running through the original idea. This method was simply to fully coat the image with the next color up, then print the entire image down to accommodate the higher density range, leaving that color as the base color, and of course all the densities below it. I mixed magenta just thick enough for a near opaque color layer and left a nice thin even coat over the image, then printed the window area as zone 7, enough time for 2-3 minutes of floating to leave the window area at zone 7, or just breaking thereof.
What that leaves is a full scale print, from zone 1 black to zone 7 white, on the white window frame, when finished. I am also being careful not to print down the spectral density, or the glow of the light in the room. That light floats between zone 7 & zone 6. Knowing your print times of any given negative image is oh so important. No different than not knowing the developing time of your negatives. Makes a big difference, in time and temperature. Those rules apply here and overlay the gum printing process pretty much exactly. When one tonal zone is done, any tonal zone before it has become permanent, and can't be altered with normal treatment afterwards. With negatives, once zone 5, or middle gray has been developed, zones 1-4 are permanent and no amount of time in the developer can change it. In gum printing, once a tonal area has been hardened by the UV light, no amount of floating will change that, or remove any more of the gum without physical manipulation, life a stiff brush or other removal tool. Once the gum has hardened, it's impervious to moisture and will last as long as the paper holding it, which has been judged to be 1000 years.
One of the reasons I am firmly against academic classes for classical printing such as gum, is that those teaching said class simply do not understand the process and certainly have never employed it. I see instructions for gum printing with print times assigned to a color, or floating a print for hours, or washing the gum print afterwards. Things one can only shake their head at and wonder what the students take away with such nonsense.
This is the second coat of gum; magenta. I use the flexible one ounce pill dispenser cups to mix the pigment into the gum, just enough color to still be able to see light through the color after mixing. This also is important. When layering the gum, to be able to see through all the colors to the base layer, adding up to the fuller image, each layer must be shear enough to be able to see through. Actually, this one is common sense. If you have ever seen or done Decoupage, you will understand the depth an image gets with increased layers of clear coat, in this case, shear layers of color stacked to make an image. A photographic watercolor.
At this point in the image, the basic texture of the wood paneling of the scene is just beginning to show up, as are the shadows. The window, and outside area is now within the tonal range of the foreground. Each subsequent layer will now be printed to that window frame, which makes up zone 7, or white with full texture. That's the goal of this printing. Now, each layer will require sufficient pigment to add further depth and texture to the image, without blocking what's already there. If I don't screw this one up it will likely be my best gum yet. I would estimate this image will need close to ten print layers to complete, bringing all the values into their correct relation to the larger image. The material in the lower foreground is brick and wood, as is the wall on the right side, all good for textural quality. That's the task.
Gum Dichromate Print
"Jars in the Window" ~
Second coating; #1 watercolor lamp black ~ #2 magenta
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