hoknok wrote:I have been sandswiching laser copies of my photography between sheets of float glass with intersting results. I want to do this without the paper backing and wondered how others may have done so. I am thinking about using overhead transparencies as well as decal transfers.
The key for me is that the image must be placed in between the glass before the fire. Not afterwards. The image also must survuve the fire. I want that semi-melted look and the cracks in the photos that resulkts when fired.
My test cases show that some do survive while others get a burn spot in the middle. This black spot may be due to the paper burning in a reduction atmosphere of co or co2 (according to William Venable). Any suggestions.
Thanks
Mike
Mike,
I am just researching on the matter, thanks to Vallace Venable generosity. So, this will be an incomplete and brief report.
First, TRASFER PAPER
I am trying thermal transfer, ironing back paper. Contact back paper worked fine. I have put the iron control in LINE or COTTON, the shiny printed surface of back paper down onto the glass, four fine cotton cloth over the paper then pressing with the hot iron during one minute (the cloth will get brown due to the temperature). Then removing immediatly the paper, otherwhise part of the Toner resin will stick back to the paper and your resolution will deteriorate.
This way the transfer was perfect, leaving no toner on the transfer paper.
Problems with transfer paper: almost all photocopy services rejected copying on my carefully cut-to-size back paper. They are afraid the paper would stick to the rollers. So I am now copying some overhead transparencies which sound promising.
Second TONER COMPOSITION
I could transfer a photocopy to the glass with excellent results and that is already a very good news. Furthermore, that image is very stable.
But when dealing with warmglass, you will need IRON in your image. The more the iron the better. Iron in Toner is BLACK magnetite Fe3O4 which oxidizes in the kiln to SEPIA Fe2O3. Wallace have already put this in his .PDF file.
Such magnetite works as developer, carrying plastic binders and pigments into the machine. Some machines uses a dual system to transfer images, retrieving all the iron prior to fusing the image onto the paper. I believe these machines are not of use for our purposes because no iron will remain in the printed image.
Other machines use a monocomponent toner, leaving the iron in the paper when fused. Furthermore, some monocomponent toners are iron free (like these of the color copiers). These are not of our interest.
The remaining iron-bearing toners will range from 9% to 55% of magnetite by weight. We will prefer the higher percentages.
I am going to carry some tests using Canon and Kyocera-Mita copiers, both monocomponent system bearing iron (according to my studies). How many iron?. Well see... . The lower the iron, the fainter the fired image.
One paragraph devoted to Hewlett Packard LaserJet printers. These printers have lowered resin and raised iron oxide content. According to MSDS, HP 4P and HP 5P black Toners have 45%-55% Iron Oxide. So these machines are almost ceramic printers!.
There are other special printers for bar-code printing on checks which Toner bears up to 60% magnetite, but you have to go to a bank to get a copy (LOL).
I have hitherto tried a single copy from a SHARP photocopier. Transferred OK but the image dissapeared with heat. I concluded SHARP uses the modern iron-free monocomponent Toner.
I will post my results later after firing my new samples. Thank you very much Wallace.
P.S.: A word on the matter of calcining paper or leaves between layers. I have found that a burn spot in the middle of the paper (or vegetal leaf) will show because glass layers seals before a complete combustion of the object preventing oxygen from entering, thus producing carbonization. To avoid this I am holding at 600°C (1112°F) for 10 minutes.