How to make a digital negative/print on transparency?

[ChrisR]

I'm currently interested in making cyanotypes, so I want to make some digital negatives. I have some transparency film from cyanotype.co.uk. It suggests using the transparency setting on the printer. Unfortunately the driver for my Canon MG5250 does not list transparency as an option; somewhere I read you can use Glossy II, and somewhere else suggested using a T-shirt printing option (the printer does have that). I'm assuming I will invert the (black and white) image in Elements or Affinity Photo.

So, any suggestions? Questions of interest include which options are best, and also whether to attempt to super-saturate the image at all to get denser blacks...

Thanks, Chris

 

[ChrisR]

With no replies to this on the Printing forum, I've asked for it to be moved here. Digital Negatives as a whole might be of interest in this forum. My plan is to make a largish (near A4) digital negative of a 135 negative, and use that to make a cyanotype. Anyway, I had a go, using a test image from Northlight Images which includes a step wedge (see http://www.northlight-images.co.uk/a-black-and-white-test-image/#strip_version). The actual test image loaded into Aperture shows even density graduations along the step wedge. I inverted it in Affinity Photo and printed onto acetate from there using the "T-shirt transfer" option on my MG5250.

Visual inspection of the result shows a pretty uneven distribution of the steps; I plan to scan it later and then measure the densities of the wedges using Aperture... I know this wouldn't be accurate, but it might tell me something.

I forgot to flip the negative left to right, as apparently you're advise to put the negative ink side towards the cyanotype paper for sharpness! Doesn't matter for the test, I guess!

 

[RaglanSurf]

With no replies to this on the Printing forum, I've asked for it to be moved here. Digital Negatives as a whole might be of interest in this forum. My plan is to make a largish (near A4) digital negative of a 135 negative, and use that to make a cyanotype. Anyway, I had a go, using a test image from Northlight Images which includes a step wedge (see http://www.northlight-images.co.uk/a-black-and-white-test-image/#strip_version). The actual test image loaded into Aperture shows even density graduations along the step wedge. I inverted it in Affinity Photo and printed onto acetate from there using the "T-shirt transfer" option on my MG5250.

Visual inspection of the result shows a pretty uneven distribution of the steps; I plan to scan it later and then measure the densities of the wedges using Aperture... I know this wouldn't be accurate, but it might tell me something.

I forgot to flip the negative left to right, as apparently you're advise to put the negative ink side towards the cyanotype paper for sharpness! Doesn't matter for the test, I guess!

Sounds fascination Chris, look forward to seeing your results.

 

[StephenM]

I don't look in the printing forum, so obviously I didn't see the original post.

You might like to look at the Focal Press book "Digital Negatives" by Reeder and Hinckel. (Spelling of names not guaranteed). I have a copy (somewhere )

 

[ChrisR]

So here is the Northlight Image made negative (as I understand it, it's freely available for download at http://www.northlight-images.co.uk/a-black-and-white-test-image/#strip_version so I hope it's OK to use a low resolution version here, for the purposes of this thread):



And here is the result after printing on acetate, drying overnight and scanning the acetate on my MG5250 scanner:



The step densities taken from Aperture of the original image and the acetate image (after conversion to black and white to remove the colour cast, which made reading the step densities difficult) are:

255 252
242 246
229 240
217 237
204 228
191 222
178 217
166 208
153 199
140 188
127 177
115 168
102 159
89 147
76 136
64 116
51 98
38 83
25 60
22 52
0 47

These measurements were only taken once, and there's some variation as you move around the step, so they are only a guide. It's clear that the process of printing and scanning has introduced a colour shift and a loss of contrast, although the result is actually better than I thought from a visual inspection. I can improve things on the scanned image by a Levels adjustment, but that's not much help for a contact print!

In practice, it should be fine for a cyanotype; I think the density range of cyanotypes is even less!

By the way, on his blog Tim Layton talks about making enlarged negatives in the dark room using Bergger Print Film... https://www.timlaytonfineart.com/bl...bergger-print-film-to-make-enlarged-negatives .

 

[ChrisR]

Not sure if I can add pngs, but here's what the numbers above translate to:



Looks like I made a measuring error at step 20 on the test image.

 

[ChrisR]

So here is the Northlight Image made negative (as I understand it, it's freely available for download at http://www.northlight-images.co.uk/a-black-and-white-test-image/#strip_version so I hope it's OK to use a low resolution version here, for the purposes of this thread):

View attachment 280054

And here is the result after printing on acetate, drying overnight and scanning the acetate on my MG5250 scanner:

View attachment 280055

...

Looking back at these two more closely, the detail in the right hand side of the first of these (the Northlight image downloaded and converted to negative) is much greater than the detail in the corresponding digital negative I made. I'm not sure yet how (or whether) this can be improved.

I have since used the digital negative as a test strip cyanotype, and also made another digital negative from an old image of mine, and made a cyanotype from that. More shortly...

 

[ChrisR]

Since I wanted to make a cyanotype, and wasn't sure how it would go, I wanted an image with a fairly strong and easily recognisable subject. I picked this image of a horseman who came to my sister's farm in 2013, wanting to stay overnight. (He was traveling across the country, just hoping to rely on public land and people's generosity to pitch his tent and graze the horse.)



Pentax MX, Kodak BW400CN.

After inversion (and flipping the image, as recommended), it looked like this:



I then printed this out on acetate at near A4 size. This is the digital negative scanned on my MG5250 at 75 spi (with a piece of while paper behind the image):



As you can, quite a lot of detail has been lost. I'm fairly sure this is a technical failure, rather than anything intrinsically wrong with the idea. One possibility is that I used the T-shirt transfer media type in Aperture; it could be that this is designed for simple images without subtle graduations. The other thing is that (for some reason) I added a small boost in contrast in the print dialogue. BTW the scan does look pretty much like the digital negative, other than the latter being transparent.

Unfortunately, I didn't make a comparison of the two negative versions before going on to try making a cyanotype from it. Perhaps that should go in the cyanotype thread...

 

[PeterSpencer]

I've only made a couple of cyanotypes, as you might have seen recently in the cyanotype thread, but I had to really boost contrast for the internegs. It seemed that the prints only worked well with really dense shadows, I mean highlights in negative terms, and correspondingly exagerated negative shadows. I liked the graphic effect myself, but that's a personal preference.

It it probably a lot to do with the cyanotype media, which in my case was pre-coated paper with a rather coarse surface. Well actually it was bit like hardboard.

I don't know if any cyanotype process can produce the level of detail you are looking for. Of course, it must depend on the paper stock and coating process.

The way to find out is to use you interneg to create a print and judge how it comes out and make adjustments accordingly.

 

[PeterSpencer]

Lastly, I'm not sure how great the effect is of having your negative sandwiched with the printed side next to or away from the sensitised paper. Certainly, using the media I tried, I wouldn't expect there to be a noticable difference. 50% of my prints were probably wrong way round but seemed to be sharp enough, to my eyes anway. But that might be because I printed them back-to-front!

 

[ChrisR]

Lastly, I'm not sure how great the effect is of having your negative sandwiched with the printed side next to or away from the sensitised paper. Certainly, using the media I tried, I wouldn't expect there to be a noticable difference. 50% of my prints were probably wrong way round but seemed to be sharp enough, to my eyes anway. But that might be because I printed them back-to-front!

My first cyanotype was the standard sort with various botanical bits sandwiched onto the paper. I did thoroughly over-expose it, but an observation from that is that some of the thicker objects didn't image well. I think the movement of the sun meant that the shadow on the cyanotype paper moved, blurring the edges. I was assuming that sort of effect was what whoever gave the piece of advice about ink to paper, meant.

 

[ChrisR]

There's a 12-page (over-) detailed description of how to make a digital negative from an image file in Cyanomicon, pages 188-200. Unfortunately I'm not sure I really understand it. Generally theres a bit of "can't see the wood for the trees" going on here! He does get into a lot of detail... He seems at various points to be recommending adjusting the gamma of the image to get a good result. Gamma is one of those topics that makes my brain hurt a little (along with anything to do with layers!, but I think he's really talking about using a curve adjustment to re-distribute the tones.