[argyllcms] Re: Ideal camera target

  • From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 2 Feb 2010 16:20:44 -0700

On 2010 Feb 2, at 4:13 PM, Klaus Karcher wrote:

> Ben Goren wrote:
>
>> On 2010 Feb 2, at 4:53 AM, Pascal de Bruijn wrote:
>>
>>> Just out of curiosity, how does one build a decent black trap?
>>
>> For  these  purposes,  I  don't think  it'll  be  too  terribly
>> difficult. I was  just planning  on using black  foamcore lined
>> with whatever kind of black felt or the like that I can find at
>> the local fabric store.
>
> Please note  that many  black textile dyes  have pretty  high IR
> reflectance. If your  camera has  no suitable IR  cutoff filter,
> this can be a problem. You  can estimate the IR reflectance with
> an  exe-one: the  reflectance  curve of  the  fabric should  not
> increase substantially beyond approx. 700nm.

Thanks for the warning -- I had  no idea! And, no, I know from the
experience of shooing red flowers  on sunny summer days that Canon
cameras tend to be quite sensitive to IR.

I'll be sure to  bring the i1 with me to the  fabric store to make
the  selection, but  the real  test will  be in  photographing the
trap. If the black levels of the trap are comparable to those when
shooting with the lens cap on,  it should meet the ``good enough''
test.

Cheers,

b&

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