Re: vacuum easel?

From: Sandy King ^lt;[email protected]>
Date: 01/20/05-06:07:16 PM Z
Message-id: <a0602040ebe15f6fce030@[]>


You will find that most members on this list are more than happy to
answer questions by newbies. With regard to your present question, I
attach below a short piece on image sharpness, based in part on an
appendix I wrote that is included in the 2nd edition of Dick Arentz's
book on platinum and palladium printing.

The Question of Sharpness

There have also been claims that the prints made with plate burners
and other HID lamps are sharper than those made with fluorescent
tubes. In my own work, in which I use both types of light sources
with vacuum frames, I can see no difference in apparent sharpness.
When using a vacuum frame perfect contact is assured between the
negative and paper during exposure. On the other hand, when making
large prints in a contact-printing frame, where it is very difficult
to maintain good contact over the entire surface area of the negative
and paper, I have found that prints made with HID lamps often have
greater apparent sharpness those made with fluorescent tubes. The
reason is obvious. Most contact printing frames in large sizes are
not capable of maintaining perfect contact between the negative and
printing paper and a lack of contact leads to scattering of the light
(and loss of sharpness) with a diffuse printing source - where many
of the lights rays pass through the negative at very low angles. With
a semi-collimated unit such as a plate burner- where the rays pass
through the negative at relatively high angles- there is much less
scattering of light.

Sandy King

>another really newbie question.... this is something i keep puzzling
>about and can't for the life of me figure out. in my reading i see
>mention of using a vacuum easel to make UV exposures. when doing a
>UV exposure, isn't the negative and sensitized material sandwiched
>between glass? why would i need a vacuum easel? { i cringe as i
>ask this because i feel like i'm missing something VERY simple here,
>and will surely smack myself in the forehead when someone explains
>it to me ;o) }
>susan ( who really can spell IQ. honest! )
>Susan Daly Voss
>lower upstate NY
Received on Thu Jan 20 18:07:44 2005

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