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RE: [Rollei] Color shift due to coatings (was something else)



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The color cast is slightly different. I thin kyou may call it hue.
I have no scientific analysis just my eyes and transparencies.
I would think that if the original coating was nearly clear and the new
coating a good blue you should see something of a change. Maybe for the 
better maybe not but it is very slight. For me its nothing worth worrying 
about.

> -----Original Message-----
> From: pkkollas  ]
> Sent: Friday, November 16, 2001 3:35 PM
> To: Rollei User Group
> Subject: [Rollei] Color shift due to coatings (was something else)
> 
> 
> A color shift?? Do you mean Hue, or saturation or lightness 
> of some specific
> hue or other?  If the Hue actually shifts, i'd like to know 
> the science
> behind shifting as a result of a slightly different response 
> in the bandpass
> of various anti-reflection coatings?  I must admit that I 
> have noticed that
> different RGB color settings are required on my enlarger when 
> printing negs
> on a roll that have pictures taken with different lenses. 
> This seems to be
> mostly noticeable when comparing Japanese lenses vs 
> German/French. It's only
> by about 3cc at most, and normally I don't try to compensate; 
> it's just
> something that I've noted. I would think that different 
> glasses would make a
> much more significant spectral response than coating 
> differences, but maybe
> I'm succumbing to my propensity to err.
> 
>  pk
> 
> Peter K wrote:
> > Jay, et al,
> > 
> > John Van Stelten recoated a Xenotar 2.8 for me. Very very good job.
> > One thing to note, it is single coated but is a different 
> coating than
> > that originally designated for the glass. The result is a 
> slight color
> > shift you will see on transparencies.
> > 
> > Peter K
> 

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<P><FONT SIZE=2>The color cast is slightly different. I thin kyou may call it hue.</FONT>
<BR><FONT SIZE=2>I have no scientific analysis just my eyes and transparencies.</FONT>
<BR><FONT SIZE=2>I would think that if the original coating was nearly clear and the new</FONT>
<BR><FONT SIZE=2>coating a good blue you should see something of a change. Maybe for the </FONT>
<BR><FONT SIZE=2>better maybe not but it is very slight. For me its nothing worth worrying </FONT>
<BR><FONT SIZE=2>about.</FONT>
</P>

<P><FONT SIZE=2>&gt; -----Original Message-----</FONT>
<BR><FONT SIZE=2>&gt; From: pkkollas  </A>]</FONT>
<BR><FONT SIZE=2>&gt; Sent: Friday, November 16, 2001 3:35 PM</FONT>
<BR><FONT SIZE=2>&gt; To: Rollei User Group</FONT>
<BR><FONT SIZE=2>&gt; Subject: [Rollei] Color shift due to coatings (was something else)</FONT>
<BR><FONT SIZE=2>&gt; </FONT>
<BR><FONT SIZE=2>&gt; </FONT>
<BR><FONT SIZE=2>&gt; A color shift?? Do you mean Hue, or saturation or lightness </FONT>
<BR><FONT SIZE=2>&gt; of some specific</FONT>
<BR><FONT SIZE=2>&gt; hue or other?&nbsp; If the Hue actually shifts, i'd like to know </FONT>
<BR><FONT SIZE=2>&gt; the science</FONT>
<BR><FONT SIZE=2>&gt; behind shifting as a result of a slightly different response </FONT>
<BR><FONT SIZE=2>&gt; in the bandpass</FONT>
<BR><FONT SIZE=2>&gt; of various anti-reflection coatings?&nbsp; I must admit that I </FONT>
<BR><FONT SIZE=2>&gt; have noticed that</FONT>
<BR><FONT SIZE=2>&gt; different RGB color settings are required on my enlarger when </FONT>
<BR><FONT SIZE=2>&gt; printing negs</FONT>
<BR><FONT SIZE=2>&gt; on a roll that have pictures taken with different lenses. </FONT>
<BR><FONT SIZE=2>&gt; This seems to be</FONT>
<BR><FONT SIZE=2>&gt; mostly noticeable when comparing Japanese lenses vs </FONT>
<BR><FONT SIZE=2>&gt; German/French. It's only</FONT>
<BR><FONT SIZE=2>&gt; by about 3cc at most, and normally I don't try to compensate; </FONT>
<BR><FONT SIZE=2>&gt; it's just</FONT>
<BR><FONT SIZE=2>&gt; something that I've noted. I would think that different </FONT>
<BR><FONT SIZE=2>&gt; glasses would make a</FONT>
<BR><FONT SIZE=2>&gt; much more significant spectral response than coating </FONT>
<BR><FONT SIZE=2>&gt; differences, but maybe</FONT>
<BR><FONT SIZE=2>&gt; I'm succumbing to my propensity to err.</FONT>
<BR><FONT SIZE=2>&gt; </FONT>
<BR><FONT SIZE=2>&gt;&nbsp; pk</FONT>
<BR><FONT SIZE=2>&gt; </FONT>
<BR><FONT SIZE=2>&gt; Peter K wrote:</FONT>
<BR><FONT SIZE=2>&gt; &gt; Jay, et al,</FONT>
<BR><FONT SIZE=2>&gt; &gt; </FONT>
<BR><FONT SIZE=2>&gt; &gt; John Van Stelten recoated a Xenotar 2.8 for me. Very very good job.</FONT>
<BR><FONT SIZE=2>&gt; &gt; One thing to note, it is single coated but is a different </FONT>
<BR><FONT SIZE=2>&gt; coating than</FONT>
<BR><FONT SIZE=2>&gt; &gt; that originally designated for the glass. The result is a </FONT>
<BR><FONT SIZE=2>&gt; slight color</FONT>
<BR><FONT SIZE=2>&gt; &gt; shift you will see on transparencies.</FONT>
<BR><FONT SIZE=2>&gt; &gt; </FONT>
<BR><FONT SIZE=2>&gt; &gt; Peter K</FONT>
<BR><FONT SIZE=2>&gt; </FONT>
</P>

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