Re: Adventures with cheap proofing lights

[CDTobie@aol.com]

In a message dated 5/13/02 4:09:14 AM, julianv@mindspring.com writes:

>> In a message dated 5/11/02 9:52:01 PM, julianv@mindspring.com writes:
>> 
>>> If anyone has more experience with Ott-Lite and can explain what is
>going on
>>> with this stuff, I would be very interested.
>>> 
>> Yes, they have some issues with consistant info and and marking of 
products.
>> I've worked extensively with a range of their products, analysing the
>> emissions and testing them for proofing purposes. The VisionSaver and
>TruColor
>> products are about 5500, with a bit if difference in glare, but pretty
>similar
>> color to each other.
>
>Is there a technical meaning for the term "glare"?  I only know the
>dictionary/colloquial meaning - unwanted or uncomfortably bright light
>interfering with one's vision.

Perhaps there's a scientific definition... but in this case it is a matter of 
the coatings, not the phosphors, so I ignored their "glare reduction" claims 
and compared the spectral emissions, and found those to be pretty much 
identical.
>
>> They are a bit weak in illuminating reds and the warm
>> end of the spectrum. The Swirls are a bit different than either... and
>while I
>> use them for othere things I do not use them for proofing. The new 
SuperD5000
>> are a real improvement, rendering better reds, offering a better color
>> rendering index, and running closer to an actual 5000k.
>> 
>> Sorry your results vary from this... it does make things confusing. By
>the
>> way, I don't find expensive proofing booths to have better rendering
>indexes,
>> or more accurate color temperature than the Otts in many cases.
>
>Yes, this is very puzzling.  What I'm seeing does not jibe with your
>descriptions at all.  I now have three 18 watt Ott-Lite bulbs for the lamp
>that I will be sending to my mother.  One bulb is a "Vision Saver" and
>the
>other two are "Super D-5000."  I cannot see any noticable difference between
>them. 

I find it to be subtle, but there is better red definition, and better 
balance (more red less blue) in the SuperD 5000. 


 And when I use them on my prints, they produce a very noticable
>greenish cast, and weak muddy reds.  The swirl bulb gives a noticably better
>screen to print match, and makes prints look better, with more
>discrimination between greens and blues, and stronger reds.

But your swirls are significantly brighter, making direct comparison 
difficult. If you place the swirls farther away, until two identical samples 
side by side, with a baffle between them, are illuminated by a SuperD5000 
bulb, and an older Swirl, I believe you will find the Swirl makes a pure 
yellow look just a bit more mustard, and a pure red look a just bit more 
purple... that the blue bias showing. If not, then your bulbs (or reflectors) 
must not match the results of testing samples OttLite sent to me. Be sure 
your reflector is not the cause of the difference... if your Swirl bulb is 
surrounded by an off-tone reflective surface, then lots of off-color light 
will be diistributed, biaqsing the results. I use a matte black backing when 
doing bulb analysis, to assure that what the spectro is reading is really 
coming from the bulb itself.
>
>I just asked my ladyfriend to make this comparison.  With no knowledge
>of
>the products, and with no prompting from me, she came up with the same
>judgment.
>
>If these Super D-5000 bulbs are supposed to be a more accurate light source,
>why do I get a better screen/print match from the swirl bulb?  I can only
>think of a few possibilities.
>
>1) Do flourescent bulbs need a burn-in period before they reach their
>targeted spectral characteristics?  I've been comparing brand new bulbs
>against a swirl bulb that is almost two years old.

They will change over time, but not nearly as fast as the filament proofing 
bulbs from Solux.
>
>2) I've noticed that illumination intensity affects my subjective perception
>of colors.  Simply moving a lamp closer to the print seems to change the
>color balance (that's why I try match the apparent brightness of screen
>and
>print).  The 20 watt swirl bulb seems to be brighter than the 18 watt Super
>D-5000, and the tube geometries and reflectors are different.

Yes, as noted above...
>
>3) Maybe my eyes and brain are not yet adapted for comparisons between
>a
>print illuminated at 5000K, and a monitor running at 6500K.  If the swirl
>bulb is 5500K, that might improve the match for me.  Or perhaps the detailed
>shape of the swirl bulb's spectrum and the characteristics of the Epson
>dyes
>just combine to produce a better match.

I find that I something warmer than 5000k is nice lighting... but sufficient 
red and yellow illumination is the issue here, and the higher the k-number be 
more blue, and the less red and yellow light the bulb is emitting.
>
>4) The Super D-5000 bulbs that I received may be different from the ones
>tested by C. David Tobie.  It could be a case of poor quality control,
>or a
>change in manufacturing source or specs.  The most disturbing possibility
>is
>that Ott-Lite just resells OEM bulbs, with limited control over their specs
>and consistency, and just slaps on whatever product descriptions they think
>will work for selling to different user markets.  I hesitate to offer such
>a
>cynical hypothesis.

OttLite does have their products built for them, but they go out of their way 
to have them custom blended, and to not allow the producer to sell that blend 
to anyone else.


  But their web site and promotional materials are full
>of inconsistent information and hyperbole.  Their sales people have also
>spouted inconsistent rubbish to me.  During one recent call, a sales rep
>told me that the Vision Saver and Super D-5000 were the same product, and
>then later in the same call she told me they were different and denied
>that
>she had earlier said they were the same.  Another Ott-droid once told me
>that my swirl bulb had the same phosphor formula as their Super D-5000
>bulbs.  He was trying to sell me more swirls at the time.  These people
>act
>like used car salesmen.

Yes, I can't disagree with any of that... I've seen it myself.

>
>I'm glad that I have one Ott-Lite bulb that works very well for proofing.
>But I have very little faith in the integrity of the company or its
>products.

I suspect what you have is a combination of bulb and reflector that balance 
out to offer the color rendition you need. I suggest you don't break or lose 
either of them!

C. David Tobie
Design Cooperative
CDTobie@designcoop.com
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