Substrates

Paper     Various Papers Fabric Considerations

The substrate provides suport for the coating and the final resting place for the noble metals forming the image.  But the substrate also can significantly influence the image through its color, surface texture, translucency, and reactions with the chemistry and processing.  Selection of the substrate is an important decision and there are many sustrates to choose from.  The best material for a substrate seems to be cotton in the form of paper or fabric.  Other materials can be used including wood pulp papers, some which can easily rival the best cotton papers.  One important criteria for substrate selection is archival longevity being that the Pt/Pd process is one of the most archival image processes.

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PAPER:

Many papers work fine for this process, but many do not.  However, some that do not work straight from the manufacturer can be made to work.  Continuously trying new papers is a good idea.  Variations have been found between different production runs of a single paper.  It is a good idea that after a good paper is found, a large quantity of that batch or lot is purchased.

In general,

• Any paper with good tooth and a resistance to bleeding should be tried.
• The paper can affect the color of the print.
• The thinner the paper, the sharper the image.
• The smother the paper, the sharper the image.
• Paper may be 100% Cotton Rag, but it may also be an archival wood pulp paper.
• Use only a paper who's longevity and quality is worthy of a platinum-palladium print.

Take heed that some manufacturers are not consistent in their use of raw materials which can lead to batch variations and inconsistencies.

Every paper has two sides (usually referred to as the nap side and the screen side).  One side is better to print on than the other.  Sometimes that side is smother.  Sometimes that side has less texture when dry after being wet.  Sometimes that side has better tooth (characteristic to grab and hold onto the coating).  Sometimes that side gives better depth to the print.  Sometimes the other side just does not work.  In any case, find the side that gives the best print and find a way to identify it.  There may be a watermark, a texture, or a screen mesh impression (when viewed with a loop).  The good side will always be the good side.  Paper is typically packaged with the same side always one direction.  In general, paper is manufactured with a nap on the front surface.  The nap is generally smother and more uniform, but many times the back side works better.

Some papers must be candled.  They may look great, but have defects hidden inside.  The final print always manages to display this defect as a black speck or spot.  (A paper notorious for this is Strathmore 500 Drawing - hard surface or plate.)  Place the paper over a light table and if anything is in there, it can be seen.  Coat and print on the "clean" areas of the paper.  Another problem indentified by candling can be pinholes.

Click here for some results for various papers.

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FABRIC:

It is strongly recommended that one master printing on paper before attempting to print on fabric.  This advice can save a lot of expense.  Fabric typically requires about three times the chemistry than that use with paper.

A high quality 100% cotton finely woven fabric works best. The best are listed here:

• Sea Isle
• Pima
• Egyptian

Any type of cotton fabric can be expected to work well.  Thicker fabrics, such as canvas, can be expected to require even more chemistry.

It is recommended to use fabric that is pre-shrunk.  Registration is already hard enough.

Silk has been found to not work with this process.  The acids drive the ferric and metal salts into the fibers where they remain to stain and deter the image.  Further research may discover a way to clear these prints.

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Considerations:

The paper or fabric should be cut larger that the negative.  Prints may be trimmed when finished. Paper should be cut ahead of time and kept in boxes aligned with the good side up.  This will let the coating step proceed quickly.  For some papers and fabric consideration may be given to the direction of the grain or weave.

Substrate Sizes:

NEGATIVE                               RANGE                    OPTIMUM

Smaller than 4x5                   6x7 to 11x14                   10x12
4x5                                          6x7 to 11x14                   11x14
8x10                                    10x12 to 16x20                  11x14
11x14                                  13x16 to 16x20                  16x20
Larger than 11x14             16x20 to full sheet             full sheet

Note: The size selected should give plenty of room for handling.  Remember, if a
           finger touches the coating, a mark may show up in the print.  Consideration
           might also be made for printing and processing equipment sizes and the cost
           of the substrate.

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