Blue gel, what blue gel? at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > The View: Video Display Hardware and Software

The View: Video Display Hardware and Software
Video Monitors and Media Players for field or studio use (all display technologies).


Reply
 
Thread Tools Search this Thread
Old October 6th, 2006, 08:26 PM   #1
Regular Crew
 
Join Date: Feb 2004
Location: Las Vegas, NV
Posts: 154
Blue gel, what blue gel?

I've been reading up on calibrating TVs or monitors and it looks as though I won't be able to get a pro monitor with a blue only switch ($$$). So can someone please tell me what the blue gel is, i.e. What do I ask for? and where do I get it?
Thanks so much,
Mike
Mike Costantini is offline   Reply With Quote
Old October 6th, 2006, 08:59 PM   #2
Wrangler
 
Join Date: Dec 2002
Location: Mays Landing, NJ
Posts: 11,543
Roscolux R80 is pretty close to primary blue, but I think you would need to double or triple it up to get something close to the desired effect. You could order a single sheet from B&H:

http://www.bhphotovideo.com/bnh/cont...ughType=search

I'm sure there are also theatrical suppliers in Las Vegas which would have these in stock. Or if you know someone who works in live theatre they can probably get you some scraps or used cut gels for nothing :-)
Boyd Ostroff is offline   Reply With Quote
Old October 7th, 2006, 06:34 AM   #3
Major Player
 
Join Date: Aug 2004
Location: Mystic Ct.
Posts: 477
What you are looking for is a Kodak Wratten filter #47 or a comparable substitute.
The Kodak filter is expensive but not as expensive as a monitor with a blue gun. :-)

There may be other gels that work, however I have always used the Wratten filter with good results.

Bill
__________________
Cinematographers Bring Shadow To Light
Bill Hamell is offline   Reply With Quote
Old October 7th, 2006, 12:54 PM   #4
Regular Crew
 
Join Date: Feb 2004
Location: Las Vegas, NV
Posts: 154
Thank you!
Mike Costantini is offline   Reply With Quote
Old October 7th, 2006, 05:50 PM   #5
Inner Circle
 
Join Date: Nov 2005
Location: LOWESTOFT - UK
Posts: 2,124
primary blue gel won't quite do the job - because it is designed for removal of the red and green component of a light source at around 3200K - as in a tungsten halogen lamp - so to do the alignment properly you need the blue colour that your monitor uses, and unlike old grade 1 broadcast crt monitors with proper phosphor calibration specs, many current monitors don't tell you what they are balanced to, CT wise?
Paul R Johnson is offline   Reply With Quote
Old October 7th, 2006, 05:53 PM   #6
Regular Crew
 
Join Date: Feb 2004
Location: Las Vegas, NV
Posts: 154
English please? lol
Mike Costantini is offline   Reply With Quote
Old October 7th, 2006, 10:47 PM   #7
Inner Circle
 
Join Date: Jun 2003
Location: Toronto, Canada
Posts: 4,750
The blue gel trick (by itself) doesn't work very well, and here's a (hopefully simple) explanation why:

--The green elements in the monitor emits light of different wavelengths. i.e. it emits some red, orange, yellow, green, blue, violet light (i.e. picture all the colors of spectrum, if a beam of light were broken up by a prism). While it emits more green light than everything else, the green elements will emit a small amount of blue light.

This blue light will get through the blue gel.

2- You can use an alternate test pattern where you have smaller boxes of the opposite color, and the test pattern flashes those boxes on/off. You can calibrate the monitor by minimizing this flashing. A .veg for Vegas can be found on my training DVD ( http://vasst.com/product.aspx?id=221...a-fa0c83fa1dcd ).

However, not all consumer TVs can be calibrated like this, since they decode the chroma in a non-standard way.

3- You can get free gel sample books/swatches. Ree, Rosco, GAM make these.

Rental houses, theatrical supply, and broadcast supply places would have these for free. i.e. B&H has them for a penny.

4- A violet/purple gel will a sharp cutoff will work just as well. The swatchbooks will have graphs... look for a graph where the stop is really steep.
Glenn Chan is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > The View: Video Display Hardware and Software

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 06:30 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network