Digital Negatives 2

Mallard

Cyanotype print on Canson Montval paper from a waxed paper PDN negative on Epson photo quality ink jet paper

 

I first considered the possibility of using photoshop and an inkjet printer to make negatives for alternative process printing early in 2000. The idea was to avoid using the darkroom for the rather time consuming task of making negatives using lith film. The method I had been trying was reversal processing of the lith film to make large negatives direct. It also seemed to me that it should be possible to effect more control over the process.

Thus began what was to be for many months an on off and uphill struggle. Not having any previous experience in either digital imaging or alternative process printing did not make matters any easier of course. I eventually began making cyanotype and vandyke prints from my medium format negatives and quickly learnt that all the problems lay with the digital negatives I had been making. It was quite clear by this time that silver negatives were much better at blocking ultraviolet light than the dye images of the inkjet negatives. Perhaps I should mention here that I was using Kodak inkjet photo transparancy film and setting the printer for photo quality paper, the problem seemed to be getting the film to hold enough ink.

The above is taken from the introduction of my first article describing my initial experiences in the making of digital negatives for contact printing alternate processes. While this was an accurate account of my experiences at the time I feel an update in the light of my subsequent work is long overdue. The turning point for me was the purchase of Dan Burkholders book " Making Digital Negatives for Contact printing" and using Pictorico film for printing my negatives. However, at the time of writing obtaining Pictorico film in the UK has become a problem. I believe that a new version of this film is being produced but it does not yet seem to be available from UK suppliers. Although I still have a small stock left I have recently been experimenting with paper negatives made on Epson photo quality inkjet paper, ( more about this later) and have seen recommendations for a transparency film made by Kentmere but I have not yet tried any of this.

Classic Jaguar car

Cyanotype Print on Saunders Waterford hot pressed paper from a PDN negative on Pictorico film

The first step in the making of a digital negative is to get an image into Photoshop. This can be a digital camera image, a negative scan, a slide scan, or a print scan. I have used all these sources for my images, the print of the Jaguar car on the left is from a colour slide scan.

The scan from either a colour or monochrome original should always be made in colour and at a resolution such that the final image size of the negative for printing ( mine are usually about 8x6) should have a resolution of 300ppi. Any other adjustments made within the scanner software will depend on your own experience, but I prefer to make these adjustments within Photoshop.

If you are working with a colour image this will need to be converted to black and white. I would sugest using the chanel mixer, but leave the image in the RGB mode, do not convert to greyscale.

Colour management

 

The above screen shot shows my photoshop colour settings

When You are satisfied with your image the next stage is to invert it to a negative and apply an adjustment curve.

One of the most common reasons why digital negatives fail to produce a good print is when the density range of the digital negative does not match the exposure scale of the alternate process being printed. This principle also applies to negatives made in camera and in the darkroom using film, in these cases exposure and development controls are used. For digital negatives an adjustment curve is applied in photoshop, this curve is specific to the alternate proces being printed, the negative substrate ie Pictorico film and the printer being used.This was one of the main points I learned from Dan Burkholders book " Making Digital Negatives for Contact Printing." The CD which comes with the book contains some ready made curves and the book explains how to modify these to suit your work flow. There are also some curves available for downloading from Dans website at www.danburkholder.com The system I am currently using for making my curves is Mark Nelsons " Precision Digital Negatives". This consists of a comprehensive manual on CD plus all the tools and curve calculators required and can be purchased at www.precisiondigitalnegatives.com

 

Cyanotype negative curve used for making the cyanotype prints in this article. Curve generated using the precision digital negative system

Staithes

Platinum toned Vandyke print on Arches Aquarelle paper. From a pictorico negative curved using the "pictorico 1270v "curve from Dan Burkholders web site.

The "pictorico 1270v " curve used for making the negative for the print opposite. Note how this curve is inverted in relation to the Cyanotype curve. This is because Dan's curves are designed to be applied to the print before inverting to the negative and the Cyanotype curve above is applied after inverting the image to a negative.

 

Printer settings

These are the settings I use for printing my digital negatives on an Epson 890 printer.

1. Choose print with preview from the file menu

2. Set source space to document

3. Set print spaceprofile to same as source

4. Click the print button

5. In your printer menu choose the media setting which works best with your printer, ie photo paper. I use photo quality glossy film. The aim is to use a media setting that allows the highest printer resolurion and lays down most ink.

6. select advanced settings.

7. Turn off high speed.

8. Set a high resolution 2880 or 1440 dpi.

9. select no colour adjustment.

 

Chapel in Castle Howard

Cyanotype print on Canson Montval paper from a PDN negative on Pictorico film

I mentioned at the begining that I had been experimenting with paper negatives and the cyanotype at the top of the page is from such a negative. I print my paper negatives on Epson photo quality inkjet paper, these negatives can be used as they are but will result in very long exposure times, particularly with a slow process such as Cyanotype.

The negatives can rendered translucent by either oiling or waxing them. For oiling either vegetable or mineral oils are suitable, I have used liquid parafin successfully and have read good reports on castor oil, this method is messy but easy. The main problem with this method is that the negatives tend to dry out and not evenly, they are usually ok for about a week and then they become less translucent.

I now wax all my paper negatives with beeswax, they read the same from day one and so far have remained the same - smooth, clear and touchable. Speckling is minimal and the wax seems to subdue any paper texture.The waxing procedure is a bit more tricky to do, but the end result is worth the extra trouble. It is possible to wax a negative by running a hot iron over the back and following this with a block of beeswax. However I use a photographic dish heater with the thermostat at it's maximum setting. When this is at it's hottest I lay the negative face down and rub a block of beeswax over the back, removing any excess with a paper towel. With a little practice this becomes quite easy, a useful tip is to lay a sheet of plain paper on the dish heater first to absorb any overspill.