Contrast Control on Saunders LPL 6700

hao922 · May 9, 2010

It seems that I could not get any contrast control from the enlarger that I just acquired.
Just to test the enlarger's contrast control. First, I tried with a low grade filter(M0, Y0), then I used a very high contrast (M170, Y0) just to try if I could get some contrast.
The two prints were almost the same. There was no contrast added to the second print.

Later on, I tested the enlarger's light source by placing a white paper under the lens while dialling the magenta filter, and I could actually see the color of the light change. If the filter is actually working, I could not think of any reason the contrast control did not work.

I have another condenser enlarger which is very easy to adjust the contrast, just by inserting different filters. (same chemical, same negative, same paper)

Could anyone help me with the issue? Thank you!

archer · May 9, 2010

Are you sure that the paper you used was variable contrast? I ask because I made that mistake before when I grabbed a pack of fixed grade paper when in a hurry. It was good for a laugh.
Denise Libby

hao922 · May 9, 2010

hi Archer, I am 100% sure. I used the same paper on a condenser enlarger, and I could change contrast by just using different filters in the filter drawer.

5stringdeath · May 9, 2010

If I remember right, there is a lever (on the left side of the head I believe) that toggles between the filters and "white light" which takes the filters out of play. I know you said you saw the color of the light changing, but it could be something to check out .... I had an LPL a couple years ago, not this exact model, so the lever may be in a different location ... or in fact your model may not have one at all, but its a thought.

If indeed the magenta and yellow filters are in play, and the color of the light is changing ... and you've ruled out the paper ... I dunno, I guess the filters could be worn out. I know in some old dichronic heads this is the case, but I wouldn't think it applies here.

edit: It does indeed have the lever somewhere. From google "White light lever for easy focusing"

ic-racer · May 9, 2010

Try comparing 170 Yellow (C0, M0) to 170 Magenta (C0, Y0) and see if you get a difference.
Fresh developer?

ozphoto · May 9, 2010

If the white light lever is in place - you'll know just by looking at the light colour.
Dial in the maximum M - if the white light lever is engaged, you won't see any colour shift.

And yes, it is on the LHS right at the top.

hao922 · May 10, 2010

I checked the enlarger. Yes I might have dailed the white level while printin.
I will check again next time when I do my next printing, and I will let you guys know what the problem is.
Thank you all for the input.

hao922 · May 11, 2010

I did a full test today and made sure that the dialled white level to the correct position in order to let the filters play (I tested on the extremes (170Y & 170M) to know that they indeed worked). CONSISTENT PAPER & CHEMISTRY
This is what I found: on the diffusion condenser, the print made on a filter grade 3.5 (0Y60M) is just slightly more contrast than the one made on a filter grade 2 (0Y0M). The contrast gap between those two grades is much smaller than the ones produced on a condenser enlarger.
Only when I used Grade 5 (170M) and doubled the exposure time at the time could I notice a very noticeable contrast boost for the same negative. But the contrast on Grade 5 still is about equivalent to what I could get from a Grade 3 filter on a condenser enlarger.

I have heard that diffusion enlarger produces less contrast prints, but I never knew that the difference is this much based on my test, if my test is correct and my diffusion enlarger functions as expected.

Could somebody please shed some light on the contrast control based on what I have done? ALso, on the web people say condenser's contrast is strong on highlight whereas diffusion's is good in shadow details? anybody has any experience on that?

Thank you all for the input.

ozphoto · May 11, 2010

Doesn't sound as if the filters are engaging properly - I have one of these enlargers, and the difference between G2 and G5 is very, very apparent.
Again, can you see the light change to very obvious M colour when you dial in 170M?

If not - it isn't engaging correctly. If it is, sounds as if they have faded really badly - surprised by this if they have. :O

hao922 · May 11, 2010

hi, ozphoto, I can see the light change from a somewhat white to a light red when I dial the Magenta filter from 0 to 170 while keeping the other two filters at 0.

richard ide · May 11, 2010

I would check your filters for fading as a 170 magenta should look very red and/or can you remove the cover and see if the filters are moving in to position properly.

hao922 · May 11, 2010

http://www.flickr.com/photos/flickhao/4597566301/in/photostream/
http://www.flickr.com/photos/flickhao/4597565531/in/photostream/
http://www.flickr.com/photos/flickhao/4598181000/in/photostream/

Hi Richard, I have posted the links for the pictures I have taken of the inside of the enlarger head (could not attach here did not know why). They show the position of the fully engaged magenta, and this is the highest position it can be levelled up using the dial. Should the filters fully levelled so that they can cover the hole through which the light comes? If the position is normal(filters fully engaged?), the only possible problem might be the fading of the color filters? that means I have to change one? anybody has done so before?

Thanks again everybody. You guys have been really helpful here.

Steve Smith · May 11, 2010

hao922 said:
the only possible problem might be the fading of the color filters?

The LPL 6700 uses dichroic filters. These cannot fade as they are not filters in the traditional sense. They use interference patterns to create the colour rather than block the part of the colour spectrum not required.

I have a 6700 and it works fine with variable contrast papers - as it should.

Steve.

perkeleellinen · May 11, 2010

I have the LPL C7700 and I've found that M170/Y0, which is supposedly grade 4.5 on Multigrade paper is actually more like grade 3 or 3.5. There's noticeable contrast differences going downwards to grade 1 but it's not possible to go harder than around grade 3.5. For most people this isn't much of an issue as they print on the lower grades, for me it is as I like to print on grade 4.

If you check the archives here, you'll notice this is a common issue. If you think the contrast is very low at M170/Y0, you could try changing the lamp.

The two solutions appear to be to either change your processing to get more contrast into the neg or buy under the lens multigrade filters.

ozphoto · May 11, 2010

Steve, your advice on changing the lamp was going to be my next suggestion as well.

ic-racer · May 11, 2010

hao922 said:
I did a full test today and made sure that the dialled white level to the correct position in order to let the filters play (I tested on the extremes (170Y & 170M) to know that they indeed worked). CONSISTENT PAPER & CHEMISTRY
This is what I found: on the diffusion condenser, the print made on a filter grade 3.5 (0Y60M) is just slightly more contrast than the one made on a filter grade 2 (0Y0M). The contrast gap between those two grades is much smaller than the ones produced on a condenser enlarger.
Only when I used Grade 5 (170M) and doubled the exposure time at the time could I notice a very noticeable contrast boost for the same negative. But the contrast on Grade 5 still is about equivalent to what I could get from a Grade 3 filter on a condenser enlarger.

I have heard that diffusion enlarger produces less contrast prints, but I never knew that the difference is this much based on my test, if my test is correct and my diffusion enlarger functions as expected.

Could somebody please shed some light on the contrast control based on what I have done? ALso, on the web people say condenser's contrast is strong on highlight whereas diffusion's is good in shadow details? anybody has any experience on that?

Thank you all for the input.

All seems OK by those results.
1) If not using combined Y/M settings, you will need more exposure with higher settings. Especially compared to white light.
2) Condenser will print with more contrast.

hao922 · May 11, 2010

perkeleellinen said:
I have the LPL C7700 and I've found that M170/Y0, which is supposedly grade 4.5 on Multigrade paper is actually more like grade 3 or 3.5. There's noticeable contrast differences going downwards to grade 1 but it's not possible to go harder than around grade 3.5. For most people this isn't much of an issue as they print on the lower grades, for me it is as I like to print on grade 4.

If you check the archives here, you'll notice this is a common issue. If you think the contrast is very low at M170/Y0, you could try changing the lamp.

The two solutions appear to be to either change your processing to get more contrast into the neg or buy under the lens multigrade filters.

Thank you guys for the help. As for the suggestion of changing the lamp, do you guys mean that lamp is not powerful/bright enough? what is the watts of the lamp that people normally use for this type of enlarger? It seems there are two types 85W82V and 100W/12V.

Thanks again

perkeleellinen · May 11, 2010

When the lamp gets old it tends to emit yellowish light which affects the contrast.

I use a 12V/100W bulb. Make sure it's a Xenophot bulb made by Osram - they're much brighter. The Osram code on mine is 64627 HLX EFP

hao922 · May 11, 2010

thank you so much Steve.
I will check it out.

hrst · May 11, 2010

You might also want to try to dial all the filters to max (170C 170M 170Y). It should block (almost) all of the light, or be very, very dim when you look at it visually. If there is, for example, quite a strong green color cast left, it would indicate problems with magenta filter.

Contrast Control on Saunders LPL 6700

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