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talajmente

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Hi All,

I'm currently working on a darkroom software which calculates the final print from a scanned bw negative, and shows it on a computer screen.

The idea is as follows:
1. Make test strips on your photographic papers.
2. Scan them, measure the densities for each strips. Draw the characteristic curve.
3. Scan a negative.
4. Apply the curve on the negative.

Here's some articles on how can a scanner be used as a densitometer (I'm using an Epson PhotoPerfection 3200 and have checked it with a Gretag densitometer)
http://www.bobwheeler.com/photo/Documents/ZoneDigital.pdf
http://www.mynett.plus.com/ep2450/2450densi.htm

And here, you can download the application:
http://www.geocities.com/talajmente/LightRoom.zip
(zip contains an .EXE, a test image and a PaperTest.csv containing some sample paper tests)

It's the very-very first version and have not been tested in the darkroom yet.

If you want to try, test, have any comments, ideas, bug report etc...
Thanks,
- Lajos
 

bobfowler

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It's got some nice potential! There are a few bugs though, but as you said, this is the first, first version.

I get errors when trying to open jpg files (Access violation at address 004F357 in module 'LightRoom.exe'. Read of address 00000000), but was able to open a bmp version of the same file. Also, your test file loads fine, but mine will only apply the changes to the left third of the image.

I'll play more with it in the next day or so and let you know what else I find.

Oh yes... I unzipped to my desktop (more than once) and the exe file doesn't have an icon, just the file name shows up.
 
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talajmente

talajmente

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Thanks Bob,

...and thanks for testing. Ill'track down the .jpg bug and freshen the zip tomorrow.
Maybe your .bmp file was a 24 bit image? This app can work only with 8 bit grayscale images - maybe it should convert other formats... hm.
Also I'm afraid that there'll be problems with the .csv file, because in the hungarian version of Excel the decimal point is comma while the cell separator is semicolon. I'm hoping that it can handle both versions.
I'd like to add some new features: after some darkroom tests it could work with multi-graded papers, objective focal length, scwartzschield-effect, etc...
Yes, it has no icon yet. (Would you like to draw one for me?? :smile: )
 

chuck94022

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I downloaded this and just messed with the test data. But I agree that it could be extremely useful to me if it is accurate. Keep it up, I like it!

-chuck
 

chuck94022

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Ok, here's a quick icon for your executable. I'm sure you can do better, but it's yours as a placeholder...

-chuck
 

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  • LightRoom.bmp
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talajmente

talajmente

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JPEG and 24bit issue eliminated, icon applicated (thanks for it), and the .csv file has been converted to "english" format, so (hopefully) you can open it with Excel and learn, how to add your own test results to the application.
(See Paper/Test/Metronome menu item too)

http://lajos.badco.ws/LightRoom.zip

Enjoy
- Lajos.
 
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talajmente

talajmente

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A new version is available at
http://lajos.badco.ws/LightRoom.zip
Some bugs were fixed, some features were added.
Some tests were run and it seems that there's as little as <5% difference between calculated image and final print.
 

L Gebhardt

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Just looking at it I would think a useful feature set would be to allow you to see side by side comparrisons of paper grade, all normallized to print white (the darkest tone in the negative) at a set value (just below paper white). For images without a true white let the user point to the area on the negative and choose the tone they want. Every thing else could then be calculated from that and the paper grades. Make this interactive so you can see the results on all paper grades at once, as you slide the tone and I would even buy this.

This could then take you to the exposure side and help you set the aperture and time from the head height.

I have thought about writing this myself but just haven't gotten around to it. It really shouldn't be that hard. If you want to make this freeware and open source project I would be glad to contribute some programming as well.
 
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talajmente

talajmente

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Hey, it's a great idea! I'll do that, however the calculator needs some polishing at first (mainly because of the schwarzschild-effect to eliminate that 5% difference - until that we can speak about 'getting rid of test strips' but 'tones').
Thanks for your offering, but I'm not sure that you'll really like to see the Delphi source code? :smile:
 

chuck94022

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What I'd love to see this evolve to over time is a full enlarging simulator. I'd like to be able to try various exposure strategies, dodging, burning, split contrast, etc.

I'd like to be able to make a mask or tool, position it in 3 space, perhaps specify a range of random motion to blur edges, set filters and exposures, and have the program "develop" the print to show me the final result, based on at least paper choices (if not development processes...)

That's not asking too much, is it? And yes, if it were in the ballpark of accurate, I'd pay for it.

-chuck
 

kjsphoto

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Delphi I love delphi!

Open source could be cool...
 

127

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On a related note...

Any contact printers (non-alternative) out there running Linux or BSD interested in trying something? (It should run on windows too, but I prefer to develop under unix).

I started work on some prototype software, and it could to with a first test. If you've got a laptop setup in the dark room, even better, as this is the hurdle thats stopped me testing it properly.

PM or email me if you're interested.

Ian
 
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