Paper Inter-Negative Anza-Borrego
Introduction
When Vicki and I had visited Anza-Borrego over the New Year we went hiking and I took a number of photographs. One I took of a Smoke tree I thought might look nice in Black and White.
This is the Smoke Tree in color taken with a Mamiya C220 TLR using Velvia 100F slide film. The trees in this area looked distressed and lacked their normal pale dusty green color and were instead this yellow color.
The difficulty with slide film in the enlarger of course is that the image will create a negative when printed. This means one must produce what is called an inter-negative. That is an intermediate image that is then reprinted (and reversed again) to create the final positive. There are two means normally used. 1) Film where a piece of black and white film is contact printed from the slide. This can then be developed and put in the enlarger and then printed directly. 2) a paper negative which is just a print of the slide at the same size as the desired final print which is then developed and then contact printed onto paper again. I chose the latter as it seemed simpler than using film. It suffers from the drawback that photo graphic paper is not pan chromatic and so reds would be represented in the final image as black. There didn't seem to be any strong red feature or content in the photo.
Using a scan of the slide I attempted to simulate the process on Photoshop. I removed the red channel in the image before converting it to Black and white. The following was the result.
This confirmed I could proceed and know what to expect.
Creating the Paper Inter-Negative
I loaded the image into the enlarger after carefully cleaning it and the negative holder of dust. (At this point I should have placed it emulsion side up rather than down which is normal. The consequence is the final print will be reversed.) I almost always do split filter printing. This means each print is a combination of my softest (#0 in my case) multi-grade filter and the my hardest or highest contrast (#5 in my case).
Usually this requires a test strip for each filter (#0 and #5) from this one picks the best exposures for black tones from the #5 filter and best exposure for whites from the #0 filter. In this case however the two step process of creating an inter-negative and then a final print increases the contrast as the transfer curves in each step multiply against each other to result in a steeper transfer curve resulting in higher contrast. So I was determined to minimise the contrast in the inter-negative. I used only a #0 filter (softest) for the inter-negative. I ran a test strip with the #0 filter and with my enlarger at f8 I determined the best exposure times were either 8 seconds or 16 seconds. I then printed two inter-negatives one at 8 seconds and the other at 16 seconds on the #0 filter. (I used Ilford MGIV Deluxe paper which has no watermark to mar the final image.)
I then developed the two prints normally. ( In my case 2 minutes in Ilford PQ Universal , 20 seconds stop, 1 minute Ilford Rapid Fixer, followed by a 2 minute wash.) They can be seen below.
The above photo is a scan of the 8 second exposure inter-negative. It appears as a negative as we would expect.
The above photo is a scan of the 16 second posture inter-negative.
Creating the Print
The print is a contact print where the inter-negative is placed emulsion (image) side down on top of fresh photo paper emulsion side up (under safelight conditions). This sandwich should have a piece of glass or clear acrylic on top to make sure the two emulsion layers are pressed together. The light from the enlarger is projected on the back of the inter-negative and it passes through the paper and is masked by the image developed in the emulsion and finally exposes the fresh photo paper underneath.
Now it is time to prepare the enlarger for making the print from the paper inter-negative. Here the enlarger is merely a light source. (There is no negative in the negative tray.) Because the light must pass through the paper the exposure must be 2 -4 stops brighter. I set the enlarger 2 stops brighter.
Now it is time to make two more test strips, this time from the inter-negative. Place the strip of MGIV paper emulsion-side up as one would normally, then place the paper inter-negative on top, emulsion (image) side down. Put the piece of glass on top. I sandwiched the whole thing in my printing frame. I then made the test strip using the following timings 4,4,8,16, and 32 seconds. This leaves a series of stripes with exposures 4,8,16,32,64 seconds. This was done twice once at #0 filter and again at #5.
Now it is a matter of choosing the exposures for each filter. In my case my first choice was #5 at 32 second and #0 at 8 seconds. I took a fresh piece of MGIV paper and placed it emulsion side up and again put the inter-negative on top image side down and the glass on top. Then exposed with the two filter times above. This resulted in the following print.
This print was too dark and very blocked up in the black sections. So next I tried another set of filter times, #5 at 16 seconds and #0 at 4 seconds. This resulted in the following.
A much better exposure of the tree but the background is still quite dark. I now have a choice of reducing the #5 filter times further or trying the other inter-negative. These prints above were unsatisfying and upon examination the inter-negative lacked detail and contrast in the mountains. The 16 second exposure inter-negative looks better in these areas. So on to that one.
Since I had somewhat dialled in the exposure I didn't create more test strips. My first print with the 16 second inter-negative was #5 at 8 seconds and #0 at 16 seconds.
Much better. A little over exposed perhaps. So another print #5 at 16 seconds and #0 at 8 seconds.
Either of these are serviceable prints.
Conclusion
Overall quite successful. I was worried that a paper inter-negative would not produce a clear print however it is quite sharp. I also worried that printing through the back of the paper would act like a diffuser and reduce the contrast. Controlling contrast is more of a problem. I did not take advantage of the key benefit of paper inter-negatives however. One can use a pencil on the back of the negative shade areas and in effect burn the print in that area. When done on a light table it is possible to be very precise in the shading and placement.
Hazards
Sharp eyes would have noticed a problem in the first print. There is a section that blurred. This is caused by insufficient contact in one area. This is highlighted below. I recall the printing easel was somewhat sprung and no doubt there was some tension that allowed a pocket to form between the inter-negative and the paper.
When Vicki and I had visited Anza-Borrego over the New Year we went hiking and I took a number of photographs. One I took of a Smoke tree I thought might look nice in Black and White.
 |
| Original Velvia 100F Slide |
This is the Smoke Tree in color taken with a Mamiya C220 TLR using Velvia 100F slide film. The trees in this area looked distressed and lacked their normal pale dusty green color and were instead this yellow color.
The difficulty with slide film in the enlarger of course is that the image will create a negative when printed. This means one must produce what is called an inter-negative. That is an intermediate image that is then reprinted (and reversed again) to create the final positive. There are two means normally used. 1) Film where a piece of black and white film is contact printed from the slide. This can then be developed and put in the enlarger and then printed directly. 2) a paper negative which is just a print of the slide at the same size as the desired final print which is then developed and then contact printed onto paper again. I chose the latter as it seemed simpler than using film. It suffers from the drawback that photo graphic paper is not pan chromatic and so reds would be represented in the final image as black. There didn't seem to be any strong red feature or content in the photo.
Using a scan of the slide I attempted to simulate the process on Photoshop. I removed the red channel in the image before converting it to Black and white. The following was the result.
 |
| Photoshop Simulation of Paper Inter-negative |
This confirmed I could proceed and know what to expect.
Creating the Paper Inter-Negative
I loaded the image into the enlarger after carefully cleaning it and the negative holder of dust. (At this point I should have placed it emulsion side up rather than down which is normal. The consequence is the final print will be reversed.) I almost always do split filter printing. This means each print is a combination of my softest (#0 in my case) multi-grade filter and the my hardest or highest contrast (#5 in my case).
Usually this requires a test strip for each filter (#0 and #5) from this one picks the best exposures for black tones from the #5 filter and best exposure for whites from the #0 filter. In this case however the two step process of creating an inter-negative and then a final print increases the contrast as the transfer curves in each step multiply against each other to result in a steeper transfer curve resulting in higher contrast. So I was determined to minimise the contrast in the inter-negative. I used only a #0 filter (softest) for the inter-negative. I ran a test strip with the #0 filter and with my enlarger at f8 I determined the best exposure times were either 8 seconds or 16 seconds. I then printed two inter-negatives one at 8 seconds and the other at 16 seconds on the #0 filter. (I used Ilford MGIV Deluxe paper which has no watermark to mar the final image.)
 |
| 64" 32" 16" 8" 4" Inter-negative test strip for filter #0 Reading left to right 64", 32", 16", 8", 4" |
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| Digital Inter-negative-1 #0 filter at 8 seconds |
The above photo is a scan of the 8 second exposure inter-negative. It appears as a negative as we would expect.
 |
| Digital Inter-negative-2 #0 filter at 16 seconds |
Creating the Print
The print is a contact print where the inter-negative is placed emulsion (image) side down on top of fresh photo paper emulsion side up (under safelight conditions). This sandwich should have a piece of glass or clear acrylic on top to make sure the two emulsion layers are pressed together. The light from the enlarger is projected on the back of the inter-negative and it passes through the paper and is masked by the image developed in the emulsion and finally exposes the fresh photo paper underneath.
Now it is time to prepare the enlarger for making the print from the paper inter-negative. Here the enlarger is merely a light source. (There is no negative in the negative tray.) Because the light must pass through the paper the exposure must be 2 -4 stops brighter. I set the enlarger 2 stops brighter.
Now it is time to make two more test strips, this time from the inter-negative. Place the strip of MGIV paper emulsion-side up as one would normally, then place the paper inter-negative on top, emulsion (image) side down. Put the piece of glass on top. I sandwiched the whole thing in my printing frame. I then made the test strip using the following timings 4,4,8,16, and 32 seconds. This leaves a series of stripes with exposures 4,8,16,32,64 seconds. This was done twice once at #0 filter and again at #5.
 |
| 64" 32" 16" 8" 4" Print test strip for filter #0 Reading left to right 64", 32", 16", 8", 4" |
 |
| 64" 32" 16" 8" 4" Print test strip for filter #5 Reading left to right 64", 32", 16", 8", 4" |
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| Print from Inter-negative-1 #0 at 8 sec #5 at 32 sec |
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| Print from Inter-negative-1 #0 at 4 sec #5 at 16 sec |
Since I had somewhat dialled in the exposure I didn't create more test strips. My first print with the 16 second inter-negative was #5 at 8 seconds and #0 at 16 seconds.
 |
| Print from Inter-negative-2 #0 at 16 sec #5 at 8 sec |
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| Print from Inter-negative-2 #0 at 8 sec #5 at 16 sec |
Conclusion
Overall quite successful. I was worried that a paper inter-negative would not produce a clear print however it is quite sharp. I also worried that printing through the back of the paper would act like a diffuser and reduce the contrast. Controlling contrast is more of a problem. I did not take advantage of the key benefit of paper inter-negatives however. One can use a pencil on the back of the negative shade areas and in effect burn the print in that area. When done on a light table it is possible to be very precise in the shading and placement.
Hazards
Sharp eyes would have noticed a problem in the first print. There is a section that blurred. This is caused by insufficient contact in one area. This is highlighted below. I recall the printing easel was somewhat sprung and no doubt there was some tension that allowed a pocket to form between the inter-negative and the paper.
 |
| Highlighted blurry area shows where proper contact was not made. |
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