Digital Negatives with Canon MG series

Discussion in 'Digital Negatives' started by Minas Stratigos, Jun 5, 2018.

  1. Minas Stratigos

    Minas Stratigos Member

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    Hi, i am struggling to produce a decent print and I am worried that my dig negatives are the issue here, has anyone tried to print a negative with Canon MG printers, dye ink? I do not have access to an EPSON printer at the moment or a Canon Pro. I would be grateful if someone can help

    thanks
     
  2. Bob Carnie

    Bob Carnie Subscriber

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    I think you may find better luck with Epson printers for digital negs. Richard Boutwell has a good system he is constantly modifying to produce good profiles for alt printing using Epson K3 inks.
     
  3. nmp

    nmp Member

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    It will help if you elaborate on what the problems with the print are? What process are you printing? How you are making the negatives? Colorized or gray? etc...
     
  4. OP
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    Minas Stratigos

    Minas Stratigos Member

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    Thanks everyone for your replies, the main issue for me is the shades of gray I don't get on paper
    - on a 255 square testgrid I have many very dark/black squares and many very bright/whites instead of gray shades.
    I am following P. Mrhar callibration method and will post soon samples.

    Process Details: 20 drop mix for a 5x5 inch berrger cot 320 paper (9 drops FO, 1 drop FO & Potassium Chlorate, 3 drops Potassium Chloroplatinate & 7 drops Sodium Chloropalladate. Temp 22C , Humidity 69-75%, I work in a controlled environment ( a storage at the company I am working for).

    Negatives are printed on Canon MG printer with print intensities (a canon setting) varying from 15 to 45 (50 is the max).

    I expose for different times (still testing) between 2 to 10 minutes at a custom made UV box with LED lights, approx 36W of LED power l= 295-405nm . I will also post a 21step wedge soon.

    thanks a lot

    Minas
     
    Last edited: Jun 6, 2018
  5. nmp

    nmp Member

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    I envy your controlled environment...:smile:

    Correct me if I am wrong, but you seem to be having adequate ink density (UV opacity) to obtain paper white in the 255 area (Dmin.) So you have already won more than half the battle for getting a good negative with a new printer. Now the issue is getting a good correction curve to redistribute those bunched up tones. Also, looks like you have not arrived at the proper exposure time yet for your process. That anchors the other side of the tonal range (Dmax.) Have you done a test strip to find this? Usually that is the first thing I fix.

    Welcome to Photrio, by the way.

    :Niranjan.
     
  6. OP
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    Minas Stratigos

    Minas Stratigos Member

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    Thanks a lot for your welcome, glad I found help here :smile:

    So you can see the strips.jpg, top is printed with intensity 35 on Canon MG series bottom with 45 (using pictorico ultra premium OHP film), both exposed for 8 minutes. What i see at from the strips is that i need to reduce exposure by two stops, hence from 8 mins to 2 mins.

    Then i made the grid (grayscale_INT40.jpg), Intensity 40 at Canon printer, exposure 2 mins.

    Let me know what do you see, if this grid is correct i will run the script and develop the gradient map. I would like also to know what a good digital negative looks like, i would like to pick a couple of good images to start with, thinking these two :https://www.stratigos.eu/still-life?lightbox=dataItem-jcm1x3ff3 and https://www.stratigos.eu/urban-architecture?lightbox=dataItem-jcm1nu264

    Cheers!
     

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  7. nmp

    nmp Member

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    Here are my observations:

    1) strips.jpg

    a) Looking at the Dmax, density on the 100% step, it seems to me that perhaps you are not getting enough exposure, even at 8 minutes. The area where there is no OHP film, the right edge (I am assuming,) the density is measurably greater which means that longer exposure can potentially give still darker Dmax. I would do a strip of sensitized paper with clear OHP film on top and expose it in 2 minute intervals to see where the first two successive exposures are indiscernible. I do not know where the highest Dmax will fall, but as it is right now, I would say the print will look dull because the shadows will not be as dark as they can be in a Pt-Pd print. In that case, perhaps greater amount of sensitizer or double-coating might be required.​

    b) Looking at the Dmin, density on the 0% step, there seems to be some "staining" when you compare that step to the uncoated area on the edges, with lower one slightly darker than the top (not sure why, would have expected be other way around based on higher ink intensity) However, in my opinion, it still is fairly good so you can live with it if an improvement can not be made. I would try and see if the highest level 50 ink density makes any difference. If you were to print for longer time to get better Dmax, Dmin will suffer some more. Hence the need to use the best possible ink density, although it is limited by possibility of greater dot gain and loss of sharpness. A colorized negative will be the next possible avenue, assuming you are not already doing it. If all else fails, you can also experiment with adding higher amount of potassium chlorate solution.​

    2) grayscale_INT40.jpg

    a) General observation is that the step matrix actually looks very good, given that no correction curve or gradient map have been applied yet. I only wish if my salt-print ones look as gentle as this.​

    b) With 2 min exposure, the Dmax has been reduced further, although not dramatically so, compared to the 8 minute exposure. However, the Dmin is now much better - nearly as white as the paper, judging from the edges. This is the trade-off. If you set the process with these conditions, you will have nice clean whites, but somewhat muted blacks.​

    Finally, both images you have chosen will be wonderful for the Pt-Pd, particularly the Calla. As would be many others on your website. Very beautiful work! I love the square format and the long exposures. (OT: I am looking for a good ND filter myself right now. Any suggestions?)

    :Niranjan.
     
  8. OP
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    Minas Stratigos

    Minas Stratigos Member

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    Thank you so much for your message, truly appreciated.

    I have done a step test using a clear pictorico film and looks like that even at 10 mins the covered and uncovered areas do not have the same black, there is a noticeable difference. I don't have with me this print to post it right now.
    I have also tried to work with a colored negative (identified the lightest color, pls see attatched scan. applied it as a new layer in screen mode to the negative). With four minutes exposure i got an all black print which really doesn't make sense, so i didn't experiment more with color negatives.
    The reason that i am trying pt/pd is that i believe my images could look very good when I manage to develop the printing skill needed (apart from the fact that i love the process). Therefore i assume that i cannot compensate with muted blacks or stained highlights. I guess the next steps are to apply the gradient map (created from the grayscale_INT40.jpg) and see what happens, maybe increasing the exposure a bit. Also need to figure out what is wrong with color negative :smile: If all these fails an EPSON printer might be the solution.

    ND Filter: for my long exposures i use 16stops ND, the Firecrest Ultra from Formatt-Hitech. I can recommend it 100% as it is doesn't give a colorcast
     

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  9. nmp

    nmp Member

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    Quick Question: When you did your colorized negative, did you invert Mrhar's HSB chart? If so, that's where you had problem. When doing this test you need to print it as is (flipped but not inverted.) It should look like what Dan is showing here, yours look negative of that:

    https://www.photrio.com/forum/threads/the-best-uv-blocking-color-for-the-digital-negatives.156527/

    Also, I am assuming the color chart was printed at 2 mins?

    :Niranjan.

    P.S. Thanks for the ND filter recommendation, I want to do color as well as B&W so color-cast is important. I will check it out. I might not get that dense - may be 10 stops.
     
  10. OP
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    Minas Stratigos

    Minas Stratigos Member

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    You are totally right, I inverted the HSB chart, didn’t realize I shouldn’t. I did two exposures with the color chart, 2 minutes and 4 minutes (the chart I posted earlier is the 4 minutes exposure). Anyway, both showed the same color (240, 40, 100). I assume i have to print the color negative again, flipped but not inverted and exposure to find my real Color, then print my grayscale using this color and see what happens.
     
  11. nmp

    nmp Member

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    it is not a total waste. You could have still read the correct value on the inverted HSB chart which would be H/S/B of 60/100/40 and used that as the color of the negative and you would have had a proper looking print. In any case, it seems to me that the Black looks equally good or better (the lowest row) than the the colored ones. I am not sure how much benefit you will get with the colorized negative. Still it would be better to repeat the test the correct way to make sure.

    As I see, the printer does not seem to be the bottle-neck yet. I would not go looking for a new Epson right now. Dmin is pretty decent at 4 minutes, matching very closely the density of bare paper (RGB of about 243 vs 246.) So the ink density and UV opacity seems to be OK. The 8 min, Dmin was around 230 which is low but could be acceptable if you manage much higher Dmax. It is not the absolute values of the Dmin and Dmax per se, but the distance between the two which gives the print its DR or the dynamic range.

    Your immediate challenge, which is irrespective of the digital negative, is improving upon the Dmax which is currently in the 80's-90's on RGB scale. ( I am assuming here that your scans are fairly good representation of the actual print) A good print would be 50's to 60's or even lower. Increasing the exposure time will increase the dark values but in going from 2 minutes to 8 minutes, it seems to have gone from 90's to the 80's. Not too great. So I doubt exposure time alone will get you to 60's. I mentioned double coating or increasing the sensitizer on single coat as one way. You can also play with the ratio of the Sensitzers A and B - higher B will give you greater contrast which in turn will allow you to push the exposure time without significantly increasing the Dmin. This sub-forum is probably not the best place to discuss this and I am by no means an expert practitioner of Pt/Pd. The Alternative Process or Hand Coated Wet Prints will be more receptive to this topic.

    :Niranjan.
     
    Last edited: Jun 8, 2018
  12. OP
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    Minas Stratigos

    Minas Stratigos Member

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    Thanks once more Niranjan for your time,

    I will print a color negative in difference exposures and see if it makes any difference, just to give it a try l I will then see if i can improve the mix, maybe order some Na2 and see what happens. The times i increased B the grain was significant and unpleasant, will post the results the moment i am ready.

    Thanks again

    Minas
     
  13. nmp

    nmp Member

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    You are quite welcome. Please do keep us posted of your progress...

    :Niranjan.
     
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