And if you do it in less than your skivvies, watch out for reflections in
the finished product.
Steve Smolian
----- Original Message -----
From: "Bruce Kinch" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, February 29, 2008 4:42 PM
Subject: Re: [ARSCLIST] LP sized scanner
> Having taught photography for 30 years, I'll comment on several posts-
> On Feb 29, 2008, at 1:06 PM, Richard L. Hess wrote:
>
>> Hi, Tom,
>>
>> The classic approach is two floods at 45-degree angle. You can use
>> lower-power lamps and with the digicam you don't need to use a filter
>> like you used to with auto white balance, but beware, you may end up with
>> more blue channel noise in the digicam image without the filter than
>> with.
>
> If you don't do a custom white balance, the color of the cover can affect
> how the camera "interprets" things
>
>>
>> If I were doing a bunch of these, I'd probably set up a tripod with
>> lights (I don't like the elCheapo copy stand I bought) and put them on
>> the floor and use my D200 and the 60 mm micro-Nikkor.
>
> I should also comment that you would want a 90 degree finder for any
> copystand or other vertical arrangement.
>>
>>
>> If you are lighting the stuff at 45 degrees look at the edges for
>> reflections where the cover material wraps around. You can do crossed
>> polarizers on lights and camera, but the lights will burn most polarizing
>> material.
>
> 45 degree is just a ballpark. A 12x12 mirror tile will be better to
> position the light. You also aim them at the far side of the copy, so the
> light "feathers" as distance increases.
>>
>> If you are happy with the colour balance, you can use Chroma 50
>> fluorescent tubes and that will provide a more even and cooler light.
>> Again 45 degrees on two sides, but now there are no round hotspots, as
>> you've got 2' line fixtures which are larger than your target. You may
>> still see some gradient across between the two tubes, adjusting them
>> should balance that out. If you get utility reflectors that's probably
>> better than bare bulbs as it provides more of an option for evening out
>> the light.
>>
>> I don't know how many you're doing, but if you're doing 100, it makes
>> sense I think to get the fluroescents and give them a try. Finding 2-foot
>> Chroma 50 lamps may be a bit of a challenge, but a good hardware store or
>> photo store ought to be able to order them for you. I'll bet B&H stocks
>> them.
>
> Chroma 50 means daylight (5000k) balance. Ideally, a bulb use with over 95
> color accuracy rating. I use Philips F32T8/950 thoughout the studio. Best
> around last time I looked, and a local bulb store had them in stock.
>>
>> Nothing is perfect, of course, and even the chroma 50s are a
>> discontinuous line spectrum, but incandescent lamps create so much heat
>> and unless you use four, are subject to hotspotting on albums and can't
>> easily be fitted with polarizing sheets (as they melt). Lower wattage
>> incandescent lamps (like 75 W or 65 W reflector floods) tend to have
>> rougher patterns than true photo lamps, and also a lower yet colour
>> temperature (maybe 2900 instead of 3200 for true, hot photo lamps). The
>> lower the colour temperature, the more relative noise in the blue channel
>> as you boost the colour balance in the camera -- that can be overcome by
>> an 80A filter.
>>
> I agree, use a daylight fluorescent if you can't do the work in your
> skivvies.
>
> Bruce
>
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