I was just upset and had too much coffee when I wrote that title and didn't mean to insult anyone. Anyway it got you all to read it:o
Originally Posted by JBrunner
But the thing I was upset with was reading suggestions (mostly in the archives, and not neccessarily by those 'in the know' on these topics) that were not applicable to someone who wants to use VC paper. NOT AZO, NOT ALT process, NOT graded paper. So suggestions for UV light, standard light bulbs, etc are pretty useless. So that leaves 'enlarger' light and its inherent collimated character which clearly shows any little dust spec or glass imprefection that gets it its way. I did not come across any posts in the archives that address this issue other than 'clean the dust off' which is a somewhat useless comment, as not all the dust can be removed in my environment.
The experiment where I show the complete elimination of dust specs and glass scratches and smudges by the simple placement of a diffuser between the enlarger light and the contact assembly was not suggested in any post that I came across in the archives or in this thread (if I missed them, my fault).
Anyway I hope you all will just understand I am just venting a little anger because I am not getting good results right off the bat after the extensive time and energy that went into restoring this 8x10 camera. I mean, one night I stayed up untill 4:30 AM to finish the bellows and frankly I am exhausted(http://www.largeformatphotography.in...d.php?t=29267).
Anyway I look forward to any comments and suggestions on the test results (http://www.largeformatphotography.in...9&postcount=90) and hope to start making awesome 8x10 prints soon.
PS anyone know what I need to do to be able to post more pictures on this forum, will 'subscribing' do it, it didn't find anything about it in the 'subscription benefits' area.
Last edited by ic-racer; 10-23-2007 at 01:39 AM. Click to view previous post history.
No offense taken. Get some rest, get up fresh and have some fun. There is not much more rewarding than a good LF contact print. I promise it will be worth the headaches.
It's the glass, not the light source. (Also, you can print and filter VC paper with a regular tungsten globe, you just have to rig the filters up.) Take the lens out of your enlarger, board and all, and you will have a larger source, but not, of course as large as a diffuser placed directly on the frame, you will still have nearly the same problem. You will see that the source has to be nearly as big as the frame before the imperfections disappear. Now that is fine for straight printing, however, eventually, when you want to dodge and burn you will want to get between the light source and the print, so you will have to go to some kind of harder source. You gotta have good clean glass. I suspect you live in a dry climate, since dust seems to be a problem. A humidifier in your work area will go a long way to holding down the dust level, as will an air purifier in addition. I have a big Honeywell that I have on a timer, runs for several hours at night, every night. Cheap, compared to wrecked prints. Long ago, in a galaxie far far away I fought the dust/scratch thing at first too. Had an old antique contact frame, weak springs, bad glass, dusty darkroom. I tried to work around it, but in the end, I found it just had to be done right.
PS I've seen dust in Ansels skies. Don't forget that spotting is part of the process. You just want to minimize how much. Rarely will you ever make a print that is perfectly free of any imperfection. It is a watermark of the process.
Last edited by JBrunner; 10-23-2007 at 01:54 AM. Click to view previous post history.
If you've got dirty or scratched glass then of course you'll get defects in your prints. It stands to reason. If you want to use a sheet of diffuser (which in effect turns your enlarger into a softbox) then that’s great, do it. But there’s really no need.
It’s well established by many, many master printers that a sheet of glass is necessary to keep the negative pressed flat against the paper. In my own experience I’ve seen soft spots on a print where there hasn’t been complete contact – and that’s when I’m using a printing frame. In fact the third scan you posted on the LF forum shows exactly what I’d expect if you’re negative doesn’t have glass (and as an aside the middle “glass & diffuser” scan suggests to me your negative isn’t completely flat under the glass anyway). I expect that your diffuser will actually be making the blurriness worse in this case (softer light). And removing the glass is not going to eliminate dust/hair defects (e.g. the right hand defect in your first scan) because that stuff is just as likely to settle on your negative or your paper.
Using a clean and unscratched piece of glass that’s either heavy enough to flatten the paper on its own or is clamped to the paper in some way (e.g. a contact printing frame) will fix the blurriness because your negative will be flat against the paper. It will fix the shadows because there will be no scratches to cast shadows (remember I said “clean and unscratched”). And if you clean the paper, negative and glass before you make the sandwich then you’ll only have to worry about dust on the surface of the glass (which you’d have to worry about anyway without the glass).
What I don’t understand is why you reject using glass when most of your problems seem to be caused by the specific piece of glass you’re using. And I don’t understand why, after having the patience to restore a large format camera you don’t have the same patience when it comes to learning how to contact print. My suggestion is that you should do what countless others have done before: find out how the master printers do it and then copy their process. That’s the quickest way to creating the stunning prints you’re aiming for.
I am in process of thinking (which model and how) and preparing to buy LF camera, and I will go 8x10, because I don't have space for 4x6 or 5x7 enlarger. That lead to contact printing. I use for now 35mm/6x7
So, after readings, lookings and thinking, for me it is clear: Get a good glass (I have Paterson's 24x30cm contact printer, so first will try that), enlarger (with proper lens/mixing chamber or condensor combination, focused lens) as light source, and I will start with multicontrast papers and will see for further.
Afer that I belive it is all in practice and adjusting process acording "real life" situation.
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First off, thanks everyone for your replies, all suggestions are welcome.
Just to keep focused, here are the goals as a hierarchy:
CONTACT PRINT USING AVAILABLE EQUIPMENT
VARIABLE CONTRAST PAPER
And again, the major problem:
WHITE SPECS SPOILING IMAGE
Solutions and consequences tested so far:
AVOID THE GLASS = no dust but poor sharpness (discussed later)
DIFFUSE THE LIGHT = no dust but poor sharpness
Things that DON"T work or are impossible:
DUSTING THE NEGATIVE UNDER SAFELIGHT. Won't work in my darkroom, it is too dark, you can't see the dust. The negative and glass have to be dusted under a high-intensity light for me to see the dust specs.
ASSUMING THE ENVIRONMENT IS DUST FREE. I already have a Honeywell (http://www.apug.org/forums/437328-post428.html. Its a great Idea to hook it to a timer to run it at night. I already have humidity control with dehumidifier, a humidifier (for different times of the year) and a sling phychrometer and a 'dial gauge' hygrometer to monitor humidity. Goals are 55 in the summer and 45 in the winter. (Without intervention the summer humidity is 65-70 and the winter humidity is 25-30)
Things yet to test:
1) PRINTING FRAME that allows one to 'pre-dust' the negative and mount it inside the frame and keep it there (nice an clean) while the back is subsequently removed and replaced repeatedly to make the test and final prints.
2) MORE PRESSURE on the glass/negative/paper unit, perhaps even vacuum or a well designed printing frame. This would allow the use of a diffuser between the enlarger and the negative.
3) OTHER LIGHT SOURCE MANIPULATIONS. Brunner's post gave me some ideas. I have a couple extra dichro. heads that could be turned into a dedicated VC light source...
The printing frame is going to be the most difficult to test because I don't have one yet I suspect that suggestions on this forum will be the most important factor in avoiding the problem of having to buy or make 2 or 3 frames to get a good one. So far Bostikc-Sullivan is tops on my list (but only from reading posts). Still about a day or two from being ready to buy one 'sight unseen' off the internet, again suggestions welcome.
Since this thread is remote from the original camera restoration thread, realize that, although I could afford any camera/lens I wanted, the goal of the 8x10 restoration was to get up and running at a cost that was consistent with the original price of the camera ($5.00 US). So it is like a challenge. Therefore, some 'controlled-light source-vaccum-printing' apparatus for $2000 is not in keeping with the spirit of the project (unless, of course I can build it myself .
Last edited by ic-racer; 10-23-2007 at 11:19 AM. Click to view previous post history.
More comments on the test results...
First and foremost I can see what I am after in the sharpest prints. They are indeed sharper than my best 4x5 negs enlarged to 8x10. Part of this whole project is a response in my part to a post (here or on LF forum) that an "8x10 contact would be superior to a 4x5 enlarged to 8x10". Always being skeptical, I wanted to see for myself, thus the incentive to get that 8x10 camera working after all these years.
Anyway, that sharp contact print really blew me away, it is really like holding a little miniature of the earth in my hand. It IS awesome and based on this, I am going to keep pushing forward with the project.
Another thing that I think was not clear is that I used the dirty scratched glass to AMPLIFY the problem I am trying to solve. For example, a few dust specs here and there are not going to show up well on a scan to post for your all to see. Also, the randomness of a few dust specs could influence the results. That is, I might get a better result because the few dust specs landed in inconspicuous places in the print, or by chance I got the glass cleaner for one test than another.
But along those lines, I was really surprised by the way the diffused light source makes all the problems go away! I am still amazed at this. It is an effect much more dramatic than I had expected. What a powerful tool (better than Photoshop because its an analog solution!)
Here is another link to the composite image:
Last edited by ic-racer; 10-23-2007 at 12:04 PM. Click to view previous post history.
I was serious when I posted I can only print at night, so I can't make any more tests right now, and there is no place I can drive today to get a contact frame (thought I may be able to cobble one together today when I get done wasting my time on the computer )
Anyway I did want to digress, and discuss the results obtained WITHOUT the glass. **CAUTION** this post may involve mathematics so pleas skip to the next post if not interested.
In the initial post I disregarded any effects of diffraction. I am not sure, but this may be an error. DIffraction is a sometimes mysterious process (one of my favorite real life examples I witnessed was being in a jet plane and seeing its 'shadow' cast as a 'bright spot' when we were at just the right distance for the diffraction pattern to show the center of the bulls-eye as light vs dark.)
Anyway, the test picture that was obtained WITHOUT the glass was not outside the bounds of the test equation. That is, the negative was NOT displaced more than 0.5 mm above the paper. Yet , this image is 'blurrier' than expected from the equation.
One possible explanation is diffraction. The pictures posted show a magnified area of the center of the image which is an image of BLADES OF GRASS that are on the other side of a small river, about 50 METERS FROM THE CAMERA.
Using the 'thin lens' formula with these numbers I can find the width of these blades of grass as they appear in the negative. Distance to grass = 50000mm, Distance to negative = 210mm, size of grass blade = 1mm, calculated size of grass blade image = 0.0042mm.
To refresh my memory, here is a simple quote from a basic web site on physics:
"The amount of bending depends on the relative size of the wavelength of light to the size of the opening. If the opening is much larger than the light's wavelength, the bending will be almost unnoticeable. However, if the two are closer in size or equal, the amount of bending is considerable..."
What I was underestimating is that light diffracts more when forced to go BETWEEN two objects rather than around one large object.
I had estimated that the light just has to go AROUND big opaque areas of silver, but, in-fact, the light is being forced to go BETWEEN the little images of the blades of grass. This is causing more diffraction than I had realized. Not sure but just a thought.
OK if you don't like math and optics you can start reading again at this point....
Just an observation...the rings can also form from uneven pressure. I packed a contact printing frame with extra padding to increase the pressure and only increased the rings. Areas directly under the springs were under greater pressure. Reducing the pressure by removing some of the extra packing got rid of the rings.
Originally Posted by JBrunner
ic-racer -- I have a couple B&S contact printing frames...good quality!
Just a quick though, and you may have already dealt with this, but...
When I use my enlarger as my light source for contact printing, I leave the lens in so I can control the light via height and f/stop. But I also make sure to rack the focus (and now I can't remember if I'm racking it full in or out) so that the schmutz that might be on the condenser glass or on the filters won't be focused by the enlarger lens.
This probably isn't that important but if you were to leave a negative carrier with glass in the enlarger, you could potentially be focusing any of the dust on the carrier onto your final print. I stopped using glass carriers so my only concern is dust on the condenser lenses or VC filters.