My problems with long exposure times with RA4. Any advice?

[Rolle]

I have printed 4x5 color negatives to max 12x16 size in the past. Now I started printing 16x20, and I have run to a couple of issues. I use Durst L1200 with CLS500 color head (250W bulb) and a Rodagon f5.6/135mm.

With my negatives I get exposure times of 30-60 seconds at f 8 on Fujicolor CA paper. Smaller aperture than f8 is impossible to use, if any burning in or dodging needs to be done, because at f11 you hardly can see the projected image on the base board.

My color analyzer is Colorstar 3000. It is completely useless with these large print sizes, it is not sensitive enough to give a reading even at print size 12x16 when a diffusor is used for an average reading.

So a couple of questions:
Rodagon 5.6/135mm: I only can use f8 or slightly larger aperture when doing 16x20. With smaller prints I always use f11. I am concerned about how good this lens is at f8? Should I get a better lens?
The analyzer: do you know a more light sensitive analyzer than Colorstar 3000? What do you do when using an analyzer and printing 16x20 or bigger size? Do you make a smaller print first or what?

Thanks for any comments.

[greenrhino]

I would start with a brand new bulb and see if that helps, That does seem a bit long from 4x5 to 16x20, 30-45 seconds is closer to the time i would get on a 30x40 or a 40x50 from a properly exposed 4x5 neg. i do think f8 is fine though, if I am using an untested lens I would us it a t f8-11.

Good Luck
Anthony

I have printed 4x5 color negatives to max 12x16 size in the past. Now I started printing 16x20, and I have run to a couple of issues. I use Durst L1200 with CLS500 color head (250W bulb) and a Rodagon f5.6/135mm.

With my negatives I get exposure times of 30-60 seconds at f 8 on Fujicolor CA paper. Smaller aperture than f8 is impossible to use, if any burning in or dodging needs to be done, because at f11 you hardly can see the projected image on the base board.

My color analyzer is Colorstar 3000. It is completely useless with these large print sizes, it is not sensitive enough to give a reading even at print size 12x16 when a diffusor is used for an average reading.

So a couple of questions:
Rodagon 5.6/135mm: I only can use f8 or slightly larger aperture when doing 16x20. With smaller prints I always use f11. I am concerned about how good this lens is at f8? Should I get a better lens?
The analyzer: do you know a more light sensitive analyzer than Colorstar 3000? What do you do when using an analyzer and printing 16x20 or bigger size? Do you make a smaller print first or what?

Thanks for any comments.

[Rolle]

I would start with a brand new bulb and see if that helps, That does seem a bit long from 4x5 to 16x20, 30-45 seconds is closer to the time i would get on a 30x40 or a 40x50 from a properly exposed 4x5 neg. i do think f8 is fine though, if I am using an untested lens I would us it a t f8-11.

Good Luck
Anthony

I am talking inches, so my exposure times are in the same ballpark as yours. In fact I messed up in the 1st posting, the inch size I am now pritnting is 20x24 = 50x60cm.
But the question is still the same: is Rodagon 135mm OK at f8, and how to make use of a color analyzer...

[SpeedGraphicMan]

Holy Cow!

Mine 16x20 exposures are roughly 6-10 seconds at f8 with a Omega Super Dichro II/250 Watt.

It is possible that:

Your negatives are way too dense.

Your paper is old.

You are not reaching a completed development with RA-4

[false_Aesthetic]

assuming you haven't ridiculously over-exposed your images (a la Jim Dow)
and that your chem/dev time is ok.

new bulb.

[Joseph Dickerson]

Another vote for a new bulb. And maybe a good/gentle cleaning of the interior of the enlarger including filter surfaces.

The Rodagon should be fine at f/8 and probably acceptable at f/5.6. Mine was.

JD

[Phil Hudson]

Check you haven't dialled in a neutral density filter as well. Some Dursts have a variable ND filter in the head. Could it be in the light path?

[Greg Blank]

Your analyzer is fine- I have one CS3000. Try spot measuring between dark and light areas and then averaging. 18 seconds is ideal but sometimes not possible.If the time goes past 25 I would open the lens aperture or get a good one that you can. Most enlarger lenses that are good quality can be used at any aperture. Good lenses are designed to be used through the whole range, if a good lens will not prodce a good print either the negative is not sharp enough or the enlarger is not aligned properly.

I have printed 4x5 color negatives to max 12x16 size in the past. Now I started printing 16x20, and I have run to a couple of issues. I use Durst L1200 with CLS500 color head (250W bulb) and a Rodagon f5.6/135mm.

With my negatives I get exposure times of 30-60 seconds at f 8 on Fujicolor CA paper. Smaller aperture than f8 is impossible to use, if any burning in or dodging needs to be done, because at f11 you hardly can see the projected image on the base board.

My color analyzer is Colorstar 3000. It is completely useless with these large print sizes, it is not sensitive enough to give a reading even at print size 12x16 when a diffusor is used for an average reading.

So a couple of questions:
Rodagon 5.6/135mm: I only can use f8 or slightly larger aperture when doing 16x20. With smaller prints I always use f11. I am concerned about how good this lens is at f8? Should I get a better lens?
The analyzer: do you know a more light sensitive analyzer than Colorstar 3000? What do you do when using an analyzer and printing 16x20 or bigger size? Do you make a smaller print first or what?

Thanks for any comments.