# Test strips



## flyingPhoto (May 30, 2021)

I have been contemplating exposure test strips for a while.   SO far it seems i am supposed to make a test print for EVERY frame before i make the real final print on it. 

Or i am supposed to do a test strip exposure via a contact print on my negatives. 

neither option makes sense as a contact print will have multiple exposure values, etc to deal with on each frame. And what works for one wont work for another frame if the rule of a test strip for each image is based on fact


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## compur (May 30, 2021)

Test strips are usually done on individual frames.

You don't necessarily always have to do test strips. For example, if all your negs on a roll have the same density range, you'd usually do test strips on the first frame. Then you may not need to do them for the others. It all depends on the images and your preferences and purpose for printing them. A print that you intend to hang on the wall would usually deserve more careful attention than one that you are just printing to show your friends how big the fish was.


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## flyingPhoto (May 30, 2021)

how would you define equal density? I have done rolls of film on one aperture, and one shutter speed, and the same box iso used.. but there were WIDE differences in density


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## Ysarex (May 30, 2021)

flyingPhoto said:


> I have been contemplating exposure test strips for a while.   SO far it seems i am supposed to make a test print for EVERY frame before i make the real final print on it.
> 
> Or i am supposed to do a test strip exposure via a contact print on my negatives.
> 
> neither option makes sense as a contact print will have multiple exposure values, etc to deal with on each frame. And what works for one wont work for another frame if the rule of a test strip for each image is based on fact


B&W printing paper will reach DMAX with normal development and X exposure. If you make a print in which the paper does not reach DMAX you have a print with no black in it -- sucks. If you expose the paper beyond the necessary time to reach DMAX then you're printing your shadow detail into black. You might want to do that for effect but normally that also sucks.

For any given enlargement size that X exposure value will of course vary but it's useful to determine the exposure time to reach DMAX for a common print size -- say 8x10. You have to account for the film base so what you're really looking for is the exposure time for and 8x10 print from _______ film stock that will print the film base to DMAX and not beyond.

Put a clear piece of film base in the neg carrier so that half the neg carrier is open air. It's easy then to focus on the cut edge of the film with the enlarger raised to print an 8x10. The open air section will expose the paper more and so reach DMAX sooner. Make 3 second test strip exposures down the paper until you find the exposure that prints the film base to DMAX (compare with the open air side of the carrier).

If you have the discipline then to correctly expose and process your film you have determined the correct exposure on that enlarger to make an 8x10 B&W print from a properly exposed and processed negative of that film stock.


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## flyingPhoto (May 30, 2021)

how would even really know if you had developed the negative correctly?


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## 480sparky (May 30, 2021)

flyingPhoto said:


> how would you define equal density? I have done rolls of film on one aperture, and one shutter speed,....


That's fine if the _lighting_ in all the frames were the same.


flyingPhoto said:


> ...and the same box iso used.


If you're shooting a roll of film, you're pretty much stuck with one ISO.



flyingPhoto said:


> but there were WIDE differences in density


Because the lighting changed between frames.  If some are lighter and some are darker, then yes, you will need to make a test strip for each frame.


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## compur (May 30, 2021)

flyingPhoto said:


> how would you define equal density?


Density *range*, I said.

Your skill in evaluating negatives will improve with experience. So will your skill in exposing negatives for density range that will print well.


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## Ysarex (May 30, 2021)

flyingPhoto said:


> how would even really know if you had developed the negative correctly?


One way is to print it on an enlarger with paper that has been tested on that enlarger for the correct exposure time through the film base to reach DMAX in the paper. If the print is too dark then the negative is under exposed and/or under developed. If the print is too light then the negative is over exposed and/or over developed.


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## flyingPhoto (May 30, 2021)

Ysarex said:


> One way is to print it on an enlarger with paper that has been tested on that enlarger for the correct exposure time through the film base to reach DMAX in the paper. If the print is too dark then the negative is under exposed and/or under developed. If the print is too light then the negative is over exposed and/or over developed.


and whats the best way to do that testing? Im still new to the terms


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## flyingPhoto (May 31, 2021)

webestang64 said:


> Just a suggestion but you should find a darkroom book. They are cheap and plentiful and will show you all the basics in darkroom printing.
> 
> I found these for $2 each at a thrift shop.


just how many times have you posted that image and qoute on this site? Just really curious as it seems to be your stock answer to most "basic' dark room questions. 

And at same time, should i spend money on a book that talks about working cibachrome when cibachrome no longer exists for LONG long time?


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## ac12 (May 31, 2021)

flyingPhoto said:


> just how many times have you posted that image and qoute on this site? Just really curious as it seems to be your stock answer to most "basic' dark room questions.
> 
> And at same time, should i spend money on a book that talks about working cibachrome when cibachrome no longer exists for LONG long time?



He does have a point.
Based on your admitted experience level, books are a very good idea.
Some are practical with little/no theory, some have a LOT of theory that can be hard to understand, and everything in between.
You have to read them to see which ones work for YOU.  And sometimes use more than just one book.
The heavy theory books, while difficult to understand now, will become easier to understand as you gain experience.

If you are printing B&W, why waste your time reading about printing Cibachrome.
Especially since you cannot print with it anyway.


*As for test strips:*

You answered your own question.

Quotes:

And what works for one _(frame)_ wont work for another frame if the rule of a test strip for each image is based on fact.

how would you define equal density?_* I have done rolls of film on one aperture, and one shutter speed, and the same box iso used..*_ _*but there were WIDE differences in density*_

End quotes:

If the negative density is very different, frame to frame, this tells me that you may not understand exposure on the camera side.  Shooting at _ONE aperture and shutter speed in different light conditions_ WILL result in different exposure on the film. And thus different negative density, from unprintable light to unprintable DARK.
IMHO, you need to understand exposure in the camera, and get a decent handle on it, BEFORE you work on printing.  Fix the source of the problem, not the result.

As for your negatives.  If as you say, the density is very different from frame to frame, then the correct print exposure will be different for each frame.   Therefore, you need to do a test strip for each frame, where the density is different.

For exposure, try using this, instead of doing a traditional test strip:








						Delta 1 Projection Print Calculator Scale 4x5"
					

Buy Delta 1 Projection Print Calculator Scale 4x5" Review Delta 1 null




					www.bhphotovideo.com
				




Density range is the difference between the clearest part of the film and the darkest (that has shadow image).
Without a meter, this is hard to determine, especially for a newbie.
The only time that I could "eyeball" the density range was when I was printing regularly, as in every day for MONTHS.  Once I cut back, to a hobby schedule, I could not eyeball it.  I had to start using a meter and/or evaluating a test print.
Negative density range affects the printing paper grade used, so this is important to understand.  Read the books.


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## webestang64 (Jun 1, 2021)

flyingPhoto said:


> just how many times have you posted that image and qoute on this site? Just really curious as it seems to be your stock answer to most "basic' dark room questions.
> 
> And at same time, should i spend money on a book that talks about working cibachrome when cibachrome no longer exists for LONG long time?


Sorry ....deleted.


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