If you are on a budget, the two mirror technique works as well as any other, though it can be a real eye-strainer and back-breaker. Have the hardware store cut two 2" strips from a 12x12" mirror tile. Scratch a hole in the silvering at 1" from the end of one mirror and put a cross-hairs around it with white tape or some such. The tile without the hole is on the easel, the one with the hole is either where the negative carrier should go or held against the lens flange, silver side down. Look through the hole and adjust the enlarger so the reflected image of the cross-hairs lines up with itself.
put a cross-hairs around it with white tape or some such.
*******
I do not understand this, but would like to.
Pure genius.
What about, a negative, with several very sharp lines across it? A few thin pencil lines on plain paper, photographed from a tripod/copy stand with a small aperature for good DOF (in case your camera isn't perfectly aligned, either) should generate a good target image.
Project that negative onto the easel and use a grain focuser to check edge-edge sharpness.
Dear Anscojohn,
Could you please explain this a bit (in simple English)?
Thank you,
Philippe
I'm also not satisified with just the laser/mirror alignment. I always double check with the grain focuser on the corners vs center.
Realize that the grain focuser that can see the edges will set you back an additional $250.
I'm also not satisified with just the laser/mirror alignment.
I always double check with the grain focuser on the
corners vs center.
I have and use the same system, so perhaps I can explain it better.
And for non-native English speakers, the photos should also help
In short, you have two mirrors, and on one (smaller) you scrape (remove) some silvering, so that you can see through the small hole you made (basically, you remove reflective surface in a small circle). Then you draw a target on the reflective surface AROUND that hole. The hole can be physical (drilled in the mirror), or you can just scrape (remove) silver reflective surface, without drilling the glass.
The photos should make everything much clearer...
My system has a DRILLED hole, with target around it, but you can also just remove the silver reflective surface, like I said. Then draw a target around the hole - either directly on the glass (like I did on mine), or first tape some clear sticky tape around the hole, and draw the target on that (if you don't have a pen that can write on glass...).
Let me know if you need additional explanations.
An image may be sharp four corners and center with
the enlarger quite out of alignment. You've heard of
Scheimpflug.
The method I've described assures correct alignment.
The method assumes the projected image to be
composed of four 90 degree angles.
With the image focused as well as it might be, test
three of the four corners with a square for a true 90
degrees. If the three measure true then the enlarger
is aligned; the image will be sharp corners and center.
No alignment tool other than a square is needed. Dan
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