All

Won this meter on Gov't Liqudation auction a year back. It works and measures higher IRE readings but doesn't do below 50 IRE. When placed in XYZ mode I get reading on high & lower IRE and also when measuring colors. I'm new to calibaration and I don't know how to determine if the meter is actually measuring the color or just throwing out number when in XYZ mode. When I make changes to the hue, lightness, or chroma of a given color on my Sharp 12K MKII DLP the meter reading do change.

Is there any tool for converting XYZ colospace to xyY? The BM-7 seems to be very accurate at high IRE.

Where can I get the XYZ target number for all primary and secondary colors? I would like to try and determine what this thing is actually doing and also capble of. It's an older model but it was a high end product at one time.


Thanks

Andre

All

Won this meter on Gov't Liqudation auction a year back. It works and measures higher IRE readings but doesn't do below 50 IRE. When placed in XYZ mode I get reading on high & lower IRE and also when measuring colors. I'm new to calibaration and I don't know how to determine if the meter is actually measuring the color or just throwing out number when in XYZ mode. When I make changes to the hue, lightness, or chroma of a given color on my Sharp 12K MKII DLP the meter reading do change.

Is there any tool for converting XYZ colospace to xyY? The BM-7 seems to be very accurate at high IRE.

Where can I get the XYZ target number for all primary and secondary colors? I would like to try and determine what this thing is actually doing and also capble of. It's an older model but it was a high end product at one time.


Thanks

Andre

x=X/(X+Y+Z)
y=Y/(X+Y+Z)
Y=Y

Given you don't know it's calibration history you won't really be able to determine whether it's giving you accurate readings without a comparison to something you trust. Does it output color temperature? If you take a reading of an overcast sky and it reads around 6000K you can say it's "in the ballpark" but not much more.

Here's a link to the BM-7 techspecs: http://www.hoffmanengineering.com/bm7_tech_specs.htm

The variable aperature should be set to 2 deg. to get more light and it supposedly has both x,y,Y and u,v,L and Temperature output modes but these require the RS-232 or GPIB interfaces.

Zoyd, Thanks for repling. I played around with it last night. I measure a 100 - 80 IRE window and I must admit the color looked real good on my Sharp 12K. I viewed 5th Element and the colors were the best I've seen on 12K so far. I also have the Colorfacts 6.0 Pro with Spyder II senser but I haven't had good luck using it.

The color seem better using the BM-7. I will try your overcast method to see what it reads. It takes pretty fast reading and the numbers are solid when reading higher IREs using x,y,Y mode. It gets iffy when trying to do the lower end.

Thanks for the link. I don't think I have the variable aperature. My says 1 deg and there is no know to adjust it.

Thank you VERY MUCH

Andre

It takes pretty fast reading and the numbers are solid when reading higher IREs using x,y,Y mode. It gets iffy when trying to do the lower end.


Try different ranges if you can, range 5 should give you the most sensitivity.

Zoyd, I read your response to Fraza on an old (07) posting
I have a BM-7 colorimeter which seems to be giving erratic readings. Can you suggest a repair lab where this unit could be sent for a checkup?
Thanks in advance Cgiff

Zoyd, I read your response to Fraza on an old (07) posting
I have a BM-7 colorimeter which seems to be giving erratic readings. Can you suggest a repair lab where this unit could be sent for a checkup?
Thanks in advance Cgiff

Google for "calibration labs". Some do cals on optical equipment such as colorimeters. Probably your best bet is to contact the manufacturer directly. They may be able to recal the piece for you or point you to someone who can.

Good luck! :)