Beseler Minolta 45a Head - Split grade printing question

[Pali K]

I finally got around to mounting this head on my enlarger and gave it a go last night. I have read up the entire manual and understand that this head works very different from traditional enlargers that are time based. I attempted to print using split grade technique that I am comfortable with but was not able to do so with consistency.

In my attempt last night, I struggled to convert my low grade and high grade test stripes to final print values. For example, I set the values to low grade (blue?) channel to 30 and then exposed the strip as you do with traditional methods going from 30 to 180 (30, 60, .... 180) and found 120 to be the ideal low grade exposure. I then repeated the process with high grade (green?) and made a similar strip and found a value of 150 that I liked for shadows.

After this I set the low grade to 120 and high grade to 150 and made the exposure and the result was an extremely overexposed paper which was almost pure black.

Puzzled with the results I tried to isolate the grades and only exposed with low grade set to 120 and high set to 0 and I still got an overexposed result.

So now I am totally confused how I could ever go about printing split grade with this head? Does a setting of 30 exposed twice not equal to 60 with this head?

I know I am missing something obvious but I can't seem to figure it out and would appreciate any help before I waste more paper.

Pali

[bob carnie]

Blue is the high grade
Green is the low grade

Fix that thinking and you will have a better starting point..

I would suggest use the head for single grade and get use to the concept before jumping into the deep end.

[Pali K]

Bob, thanks for the clarification there on the colors.

If you don't mind can you please explain what is wrong with my thinking that an exposure of 30 twice is not the same as 60 once.

Could this be reciprocity failure since 30 twice is approximately 20 seconds exposure and 60 once is 10 seconds exposure due to how this head works?

[ic-racer]

As you have found out, "Split Grade" printing does not work like that. This is because the mid tones are sensitive to both light colors, so the two exposures make the overall print too dark if you just add them that way. You need to add the high contrast exposure to the already exposed low contrast image when making the high contrast test print.

http://www.lesmcleanphotography.com/articles.php?page=full&article=21

[Pali K]

As you have found out, "Split Grade" printing does not work like that. This is because the mid tones are sensitive to both light colors, so the two exposures make the overall print too dark if you just add them that way. You need to add the high contrast exposure to the already exposed low contrast image when making the high contrast test print.

http://www.lesmcleanphotography.com/articles.php?page=full&article=21

Thank you - that certainly makes more sense. In the past, I have been working with graded filters where I would expose using grade 00 and grade 5 independently and the final exposures remained relatively consistent. However I know that the image I tried with Minolta was did result in more "mid-tones" overlap between the low and high grade exposures.

I'll try to follow your recommended process when I try this again. Thank you!

[Jerry Bodine]

I'll add a plug for "Way Beyond Monochrome, Ed. 2" as the best instruction for Split Printing that I've seen, as well as coverage of most everything photographic. Check it out on Amazon.

http://www.amazon.com/Way-Beyond-Monochrome-Traditional-Photography/dp/0240816250/ref=sr_1_1?s=books&ie=UTF8&qid=1442259806&sr=1-1&keywords=way+beyond+monochrome

[EdSawyer]

That is a great book. At least one of the authors is active on the forums (LFPF, APUG, etc.).