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Posted by Paul Cooper on March 14, 2007, 7:05 am
Please log in for more thread options On 13 Mar 2007 14:06:42 -0700, dshtykalo@gmail.com wrote:
>>
>> > can someone tell me the advantages and disadvantages to color and
>> > black & whiteaerialphotography.
>>
>> > thanks in advance!
>>
>> In the days when film was the medium of choice...
>>
>> B&W advantages:
>>
>> 1. Stable film base layer + high grey level resolution = precise geometric
info
>> 2. Film stable over time (and reproduced well when making copies, for
>> example onto glass plates)
>>
>> Color disadvantages:
>>
>> 1. Thin film base layer (to accommodate dye layers) + three "gel" dye layers
>> leads to geometric instability (in processing and subsequent storage).
>> 2. Impossibility to achieve perfect focus on three dye layers simultaneously
>> implies loss of spatial resolution (compared to equivalent B&W).
>> 3. Dye layers not stable over time (i.e., "colors" change over time)
>> 4. Degradation in spectral quality significant when producing copies
>> (i.e., loss of quality significant if not working with the original
>> film).
>>
>> Color advantages:
>>
>> 1. Gives more (spectral) information about what you're seeing, rather than
>> simply about where it is located (geometric).
>>
>> The major driver foraerialphotographyhistorically was map making --
>> getting things in the right place (geometrically) was paramount.
>> Traditionalists frowned upon the use of color film in mapping for
>> reasons I've cited.
>>
>> No doubt there's more to say. But, I've given you a start.
>
>Much appreciated Bob.
>
>The main purpose will be for display and the occasionally
>measurement. Our last collection was from 2002, but our city has
>grown considerably since then and I want to integrate them into our
>online mapping software. Our engineering dept will be using them from
>time to time and they were skeptical of the color photos but I think
>they will do just fine for what they need.
>
>Thanks again!
>
>
A further advantage of colour for some purposes is that you can use
infra-red sensitive film, which is very useful for botanists and crop
biologists who can then see how much chlorophyll (which reflects
strongly in infrared) is present.
Paul
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