Adjusting contrast for digital projectors

Have you tried running Adobe Gamma using the projected image as a reference? If this is not available, the display driver may have a gamma adjustment. The location of the display control panel depends on whether you are using a Mac or PC.
—

Mike Russell
www.curvemeister.com

I don’t use a projector, so I can’t help with your original question, but you may or may not know that the Spyder2Pro Studio kit comes with all the necessary evils to profile your projector so you wouldn’t have any of these issues in the future.

On Wed, 01 Feb 2006 16:07:09 -0800, Paul Furman found
these unused words floating about:

I’m preparing some photos for a slide show on a digital projector and I know those awful things boost contrast so I’m thinking of reducing contrast on the images.

My projector bulb is burned out at the moment though so I can’t test. Maybe someone can test this or already knows the appropriate adjustment. I think it’s more a matter of blocking up shadows than blowing highlights (though I’m not sure) so maybe with a photoshop levels adjustment on the lower ‘output’ slider to cut off to 50-255 (starting at 0-255).

Or will this even work? It’s a shame to see the photos butchered on those projectors!

If you have a friend with a laptop and an LCD screen you can approximater the butchery.

FWIW, I’d go with a gamma or curve adjustment, not contrast!

IF you’ve got a good projector, it too will have a gamma option – perhaps you can get the setup tech to use it. Furnish a 16 step greyscale as a ‘test’.

J. A. Mc. wrote:

On Wed, 01 Feb 2006 16:07:09 -0800, Paul Furman found
these unused words floating about:

I’m preparing some photos for a slide show on a digital projector and I know those awful things boost contrast so I’m thinking of reducing contrast on the images.

My friend is going to show them on his projector, I know it boosts contrast similar to mine and I don’t think there is any adjustment. I’ll probably not be able get him to set it up for tests in the evening.

If you have a friend with a laptop and an LCD screen you can approximater the butchery.

FWIW, I’d go with a gamma or curve adjustment, not contrast!

Hmmm, gamma is more like the brightness of middle tones and I think the issue is really contrast. Middle tones are probably about correct but colors get oversaturated & shadows blocked up.

IF you’ve got a good projector, it too will have a gamma option – perhaps you can get the setup tech to use it. Furnish a 16 step greyscale as a ‘test’.

Mike Russell wrote:

Have you tried running Adobe Gamma using the projected image as a reference? If this is not available, the display driver may have a gamma adjustment. The location of the display control panel depends on whether you are using a Mac or PC.

The projector to be used is a mac, mine is a pc. Is this something that can be adjusted on the computer? I doubt his has adjustment in the projector, mine doesn’t & his is smaller. I think they make them high contrast so it works in a partly lit room like for business meetings.

"Paul Furman" wrote in message

Mike Russell wrote:

Have you tried running Adobe Gamma using the projected image as a reference? If this is not available, the display driver may have a gamma adjustment. The location of the display control panel depends on whether you are using a Mac or PC.

The projector to be used is a mac, mine is a pc. Is this something that can be adjusted on the computer? I doubt his has adjustment in the projector, mine doesn’t & his is smaller. I think they make them high contrast so it works in a partly lit room like for business meetings.

I’d recommend that you install Adobe Gamma on the Mac, if you have access to the Mac version. Run it in wizard mode, and try to adjust it according to the instructions. If you can get things looking good – and there are no guarantees – you’re set. Another possibility is to use the display control panel – some drivers have adjustments for gamma and/or brightness and contrast.

Another trick I’ve heard of – from Andrew Rodney – is using the Eye One Color. It’s designed to be used with a CRT or an LCD, but if you point it backwards, it can be fooled into calibrating a projector. Cool, huh?

If you post the model number of the projector, someone may post with more direct experience.
—

Mike Russell
www.curvemeister.com

Our camera club just purchased a digital projector. We ran Adobe Gamma and the pictures still looked too contrasty. We ran it again, this time ignoring the first step prescribed by the wizard, to set the monitor to the maximum contrast. We put the contrast (using the projector controls) back to the default value. (It allows plus or minus settings up to 14.) We then did the rest of the setup as called for in Adobe Gamma, with the box unchecked for "view single gamma only" We found it helpful to defocus the projector slightly when doing the setups for red, green and blue. With the setup this way the pictures were a very close match to what was seen on the monitor. Another thing we found was that the projectors have a very short projector to screen distance and it is tempting to angle it upward and use the keystoning control to make the picture rectangular. That results in the bottom of the screen being much lighter than the top. We took steps to raise the projector so it is parallel to the screen to solve this problem.

On Wed, 01 Feb 2006 17:19:22 -0800, Paul Furman found
these unused words floating about:

J. A. Mc. wrote:

On Wed, 01 Feb 2006 16:07:09 -0800, Paul Furman found
these unused words floating about:

I’m preparing some photos for a slide show on a digital projector and I know those awful things boost contrast so I’m thinking of reducing contrast on the images.

My friend is going to show them on his projector, I know it boosts contrast similar to mine and I don’t think there is any adjustment. I’ll probably not be able get him to set it up for tests in the evening.

If you have a friend with a laptop and an LCD screen you can approximater the butchery.

FWIW, I’d go with a gamma or curve adjustment, not contrast!

Hmmm, gamma is more like the brightness of middle tones and I think the issue is really contrast. Middle tones are probably about correct but colors get oversaturated & shadows blocked up.

IF you’ve got a good projector, it too will have a gamma option – perhaps you can get the setup tech to use it. Furnish a 16 step greyscale as a ‘test’.

Video Gamma is a bit different than photoshop’s ‘gamma’. It’s used to stretch the black areas and lightly compress the upper highlights.

Don’t forget too, that photographic imagery goes to "0" black. Video cameras never go below "20". Also Video camera "white’ is really more like "224". The video space allows higher levels, but they are for reflections and often are clipped. LCDs exacerbate the clipping ‘look’.

On Thu, 2 Feb 2006 11:13:02 -0500, "John Forest" found these unused words floating about:

Our camera club just purchased a digital projector. We ran Adobe Gamma and the pictures still looked too contrasty. We ran it again, this time ignoring the first step prescribed by the wizard, to set the monitor to the maximum contrast. We put the contrast (using the projector controls) back to the default value. (It allows plus or minus settings up to 14.) We then did the rest of the setup as called for in Adobe Gamma, with the box unchecked for "view single gamma only" We found it helpful to defocus the projector slightly when doing the setups for red, green and blue. With the setup this way the pictures were a very close match to what was seen on the monitor. Another thing we found was that the projectors have a very short projector to screen distance and it is tempting to angle it upward and use the keystoning control to make the picture rectangular. That results in the bottom of the screen being much lighter than the top. We took steps to raise the projector so it is parallel to the screen to solve this problem.

Better projectors have allowed for this with a lens shift mechanism, similar to Perspective Control lenses or a swing lens in a portrait camera.

Projection and Video ‘space’ is different from monitor space as far as levels go.

J. A. Mc. wrote:

On Thu, 2 Feb 2006 11:13:02 -0500, "John Forest" found these unused words floating about:

Our camera club just purchased a digital projector. We ran Adobe Gamma and the pictures still looked too contrasty. We ran it again, this time ignoring the first step prescribed by the wizard, to set the monitor to the maximum contrast. We put the contrast (using the projector controls) back to the default value. (It allows plus or minus settings up to 14.) We then did the rest of the setup as called for in Adobe Gamma, with the box unchecked for "view single gamma only" We found it helpful to defocus the projector slightly when doing the setups for red, green and blue. With the setup this way the pictures were a very close match to what was seen on the monitor. Another thing we found was that the projectors have a very short projector to screen distance and it is tempting to angle it upward and use the keystoning control to make the picture rectangular. That results in the bottom of the screen being much lighter than the top. We took steps to raise the projector so it is parallel to the screen to solve this problem.

Better projectors have allowed for this with a lens shift mechanism, similar to Perspective Control lenses or a swing lens in a portrait camera.
Projection and Video ‘space’ is different from monitor space as far as levels go.

My projector is a Dell 2300MP. Holy shit, the replacement bulb is $350! Anyways it defaults to keystone correction assuming it’s pointing up from a conference table and that’s adjustable in the menu but any adjustment in the menu seems to put it into instability causing the image to drift to the side & requiring ‘reset-all’ to fix. When I get another bulb I’ll see if it’s possible to adjust contrast for profiling. http://www.projectorcentral.com/Dell-2300MP-user-reviews.htm http://www.pcmag.com/article2/0,1759,1710890,00.asp

On Thu, 02 Feb 2006 10:13:02 -0800, Paul Furman found
these unused words floating about:

J. A. Mc. wrote:

On Thu, 2 Feb 2006 11:13:02 -0500, "John Forest" found these unused words floating about:

Our camera club just purchased a digital projector. We ran Adobe Gamma and the pictures still looked too contrasty. We ran it again, this time ignoring the first step prescribed by the wizard, to set the monitor to the maximum contrast. We put the contrast (using the projector controls) back to the default value. (It allows plus or minus settings up to 14.) We then did the rest of the setup as called for in Adobe Gamma, with the box unchecked for "view single gamma only" We found it helpful to defocus the projector slightly when doing the setups for red, green and blue. With the setup this way the pictures were a very close match to what was seen on the monitor. Another thing we found was that the projectors have a very short projector to screen distance and it is tempting to angle it upward and use the keystoning control to make the picture rectangular. That results in the bottom of the screen being much lighter than the top. We took steps to raise the projector so it is parallel to the screen to solve this problem.

Better projectors have allowed for this with a lens shift mechanism, similar to Perspective Control lenses or a swing lens in a portrait camera.
Projection and Video ‘space’ is different from monitor space as far as levels go.

My projector is a Dell 2300MP. Holy shit, the replacement bulb is $350! Anyways it defaults to keystone correction assuming it’s pointing up from a conference table and that’s adjustable in the menu but any adjustment in the menu seems to put it into instability causing the image to drift to the side & requiring ‘reset-all’ to fix. When I get another bulb I’ll see if it’s possible to adjust contrast for profiling. http://www.projectorcentral.com/Dell-2300MP-user-reviews.htm http://www.pcmag.com/article2/0,1759,1710890,00.asp

Sorry, I don’t have the tech setup papers for any Dell machines. If it ‘defaults’ to keystone correcting, then there’s no lens shift.

That price on the bulb is ‘cheap’ – the ones we use are $800 to $1500! <G> When you consider that slide projector bulbs last about 30 hours and run $20, you should be paying double that for your 1,000 hours. <G>