Question on Pre-flash in Darkroom Printing

[raytoei@gmail.com]

Hi,

I have several questions on pre-flash.

assuming that pre-flash has been calculated at 1 second exposure, this means that i expose the paper (in this case RC) to 1 second, without the negative image. Is this correct ?

Also, if the basic exposure of the image is calculated at 8 seconds at grade 3. Is the pre-flash of 1 second included in the 8 seconds ?

thanks

raytoei

 

[gns]

Yes, the preflash is done without the negative. 1 second seems short (only because it might be difficult to keep the exposure consistent sheet to sheet). How did you "Calculate" the time? The method I learned was to lay an opaque object across the paper (like a metal ruler), then make a series of exposures (like a test strip). Process the sheet and then look for the longest exposure where there is no difference between the covered portion and exposed portion of the paper. After preflashing, make an exposure test print to get a starting point.

Cheers,
Gary

 

[raytoei@gmail.com]

gns,

thanks.

I am currently reading on a printing book by Larry Bartlett. The method described is similar to yours in calculating pre-flash, ie. 1 second interval using a strip and visually inspecting the prints for shadow change.

Just so I understand, are you saying that after pre-flash, I do a exposure test strip to determine the correct exposure ? Does this mean that pre-flash timing works across paper in the same pack ?

thanks!

raytoei

 

[gns]

Yes, after preflash, treat as normal.
The paper should be consistent within one box. I would be more concerned with consistency of the 1 second exposure than with consistency of the paper.

 

[Fawley]

I have just started reading about preflashing and fogging myself in Eddie Ephraums book "Creative Elements". He talks about making a test strip by starting at 2 secs at F22 and then increasing exposure in 1/4 or 1/2 stop ( not 1 sec) increments. He also comments on the need to determine how much the flash will effect overall print exposure. He gives some tremendous examples of useing flashing.