At 1:1 with 2400 dpi scan... I would guess that's a factor more of 10x or more enlargement from the film size? I don't know how to translate it, but I would notice it in a print of maybe 14x17 of a 4x5 sheet of film?
At issue was the difference in agitation, not different developers. Suppose you developed two sheets of 4x5 HP5 to the same contrast index in Rodinal, one using intermittent agitation (say every minute), the other using continuous agitation. You're telling me you see differences, particularly in edge effects, at an enlargement factor of 2x?
Thank you, at least someone understands. And thanks for the advice.
There are several reasons why one doesn't want to dim light bulbs in an enlarger: first, it's hard to get the same dynamic range that a lens offers you between F/4 and F/32. Second, if you dim a light bulb you change its temperature ---> its light spectrum ----> the balance between green and blue light ---> paper grade. Not good. Third, stopping down a lens one or two stops improves its sharpness in most cases, especially older designs. So no, you really don't want to dim an enlarger lamp, I have no idea why Durst ever did that, and the Durst Laborator 138 that I use on a weekly basis works with lenses that have variable apertures.
[snip]
CORRECTION
Rudeofus,
You are correct. The exposure was controlled at FULL voltage... and the time was varied by the timer.
I must have had a brain-phart when I was typing all that out. The voltage was adjusted when I was making B/W negatives from ultra-microtome tissue sections that were then treated to differential staining. Using the point source in the 138S I was able to make 4x5 B/W negatives up to (about) 25:1 magnification and achive a higher 'resolution' image than one could get from most microscopes at that magnification.
The mounted section would be inserted into the negative holder and "projected" onto sheet film in a film holder (supported on a wooden support that allowed for the film to remain parallel to the section in the negative holder).
There was a paper published in the Journal of Biological Photography that describes the technique more fully....
I'll hunt and see where that particular issue is 'hidden away'.
Ken
At 1:1 with 2400 dpi scan... I would guess that's a factor more of 10x or more enlargement from the film size? I don't know how to translate it, but I would notice it in a print of maybe 14x17 of a 4x5 sheet of film?
I'm going to assume you are viewing this "on screen" at 1:1 (1dot:1Pixel)
2400 dots per inch x 5" original long side / 72 Pixels per inch (screen resolution 72 ppi) = 166.66666667" long side on screen / 5' original long side = magnification factor 33.3333333
So, ya gonna print at 133.333333336" x 166.66666667" ?
Is that anywhere near the real print size you intend to print?
I think my screen is high DPI I don't know if that matters?
Not quite that big normally no.
Really? That big? It's in the Adobe Lightroom 4 program, I'm not sure how they interpret 1:1 but the flat screen monitor I use displays bigger than my Mac laptop "retina" display.
All I know is I can see it with a scanner, so if I can see it with a scanner at 2400 or 3200 dpi then it's there (according to the film guys who say that "crappy" scanners can't touch optical prints. So why not make the best images I can make, so in the future if I want to print BIG I don't have to worry about the edge issues.
Anyway will continue to test DD-X for now till FX-39 comes in stock.
I think my screen is high DPI I don't know if that matters?
The DPI of your screen is easily calculated.
If your resolution is, e.g. 1920 x 1080.
And the vertical dimension of the screen is 12.96 inches (as an example), then the screen resolution expressed in pixels per inch is:
1080/12.96 = 83
If your screen is just 10.8 inches high, the screen resolution expressed in pixels per inch is:
1080/10.8 = 100.
What you see at 1:1 is a combination of:
a) what is on the film; and
b) the distortions added by the scanning process; and
c) the interpolation added by scanning at 2400 ppi, when the optical resolution of your scanner is probably no greater than 1700 ppi; and
d) the distortions added by the analog to digital conversion needed to create a digital file from an analog result.
My screen is a "higher def" screen.
Also, after lots of research I've found that my Epson V750 doesn't start interpolating until 4800dpi so I always scan below that.
What you see at 1:1 is a combination of:
a) what is on the film; and
b) the distortions added by the scanning process; and
c) the interpolation added by scanning at 2400 ppi, when the optical resolution of your scanner is probably no greater than 1700 ppi; and
d) the distortions added by the analog to digital conversion needed to create a digital file from an analog result.
So 96? Real number please, "higher def" has no "real" meaning. The reason this is important is to be able to compare apples to apples.
The only reason I've gone this far into the digital weeds is to clear up a common digital misconception about it's relationship to film and paper.
This isn't a digital forum, if you want to get into the weeds of interpolation and claims of my scans are good enough and why one might want to work at 1:1 or really find out what it takes to do great scans and all that stuff, please, take it to DPUG or Dead Link Removed
I looked it up, it's 220ppi ...
Good, now you can do the math.
You need to verify that it's "soft settings" are set to it's "native" X by Y or it will add it's very own layer of interpolation on top of all the other digital issues and skew the sharpness even more.
My screen is a "higher def" screen.
Also, after lots of research I've found that my Epson V750 doesn't start interpolating until 4800dpi so I always scan below that.
The Epson might have a sensor resolution of 4800, but I can guarantee you that its fixed focus lenses are completely incapable of delivering 4800dpi resolution. Not only are they fixed focus, but they are scanning through a relatively thick sheet of glass, onto film media which is held by flimsy plastic holders with little, to no, real tension on the film. The only 4000+ dpi scanners out there are the Nikon 8/9000 (4000dpi), the Minolta Scan Multi Pro (4800dpi). These two scanners need glass holders, preferably modified to be top-side only optical grade AN glass, with no glass on the bottom to deliver the best reproduction quality possible. The other option is a Hasselblad/Imacon Flextight X series (a hell of a lot of DPI). The Flextights are the only real, modern, (non SCSI) "consumer viable" film scanners that are capable of handling sheet film, and they run well over 5000 dollars (a new one is closer to 20k).
I'm talking this kind of resolution from 400 speed 35mm film.
And yes, Retina displays are extraordinarily good...Stone sees much more realistic rendering of continuous tone than most others without high density displays will.
Thanks, that's why I said UNDER 4800, so 3200 or 2400 is all I will do, I don't fiddle with the "in between" numbers just the multiples given... IE 800,1200,2400,3200 etc
Anyway this isn't about scanning just confirms at least that I'm seeing more detail than most so that explains why I see more and it bothers me more.
Anyway I won't even be home till Tuesday.
Camera lens was a Dual-Range Summicron 50/2 at 5.6 or 8.
What is a dual range lens?
Just to clarify,the example I just posted is from my Minolta SMPro at 4800 dpi, film is HP5+, developed in Rodinal 1:50 most likely. Camera lens was a Dual-Range Summicron 50/2 at 5.6 or 8. I would highly advise that you invest in a betterscanning holder...your flatbed scans will improve dramatically once you get it dialed in.
I own and use the betterscanning holder...
Then you're in good shape
Get SilverFast under control and you'll have far more malleable files.
I own and use the betterscanning holder...
Now all you need is an Imacon, and the discussion will finally be over.
I don't need a malleable file, if it's shot correctly I don't need to mess with it at all.
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