inspired by, the ''a beam'' etc

Just wanted to update, and mention that I received my high-contrast polarizer from polarization.com. They shipped it VERY fast from TX to MA.

Im replacing the front polarizer on my 8.9" WSVGA (1024X600) LCD.
This could be a good experiment aimed at falsification or confrimation in regards to any gain(or loss ) in contrast, because my panel has a low contrast ratio of 150:1

No matter what this will be an improvment for me because i have some really stubborn glue residue, and grainyness on the factory polar from my AG removal.

So Im now wondering if there's somthing that WILL eat my polarizer.
After a 24 hour soak, i still need to apply force to peel it up. I would just do the full dunkeroo, but i want to keep my rear polarizer.

Anybody have a recomendation of a stripping chemical that will eat or soften the polarizer, but not likley damadge my "glass" (polysillicon)

I don't see pics? What the funky grille mon?

I'm also interested in seeing some before and afters.

Sometimes the acrylic glue that bonds the polarizer to the glass is water soluble. But the commercial way is to heat the glue up as it is heat activated. Know one has confirmed any safe ways to do this.

But what you should be able to do is go very slowly and carefully pulling the thing up without too much trouble, and then worry about removing the glue that's left over later (with water or window cleaner). Is it really that well bonded?

The water soak is really never going to make it all the way through your polarizer.

No-one has done a replacement since this thread started.

Mark

Maybe add warm water as you peel it up?

sorry here are some examples with dual SHC

first pic is optimised for full dark room usage

second is too far past for daylight usage,, just simply to shoe how linear these poalrs are,, the 3dlens, at this point of rotation has opposite corner problems... IE top left dark,,, bott left dark,, and top right light,,, and bott left light

and wether you use 90 degree or 45 degree,, all is good

however,,,, at 90 degree config,, seems a tad brighter,,, but need to prove it, I also still have to do a vertical arc config with this too, because I suspect it will improve yet again,,,,

to do all of this requires many configs,,,, time time time time....

but I will get to do all of these configs soon tho

Click to view attachment

Click to view attachment

another note

if you look at the wheel where it is the white to black grey scale, take note of the clear seperation of the last two grey to black rectangles,,, normally this is hard to achieve, with out losing the white end,,

another note again

now everyone goes on about colour temps,,, well I have to say with these SHC polars,, the whites are stunningly crisp and pure white,, (real white)

so the reason why many have odd results, with same lamps and different panels, I would postulate that these are the varations in panel materials too,, but this can be countered for by correct adjustment,, of panel/software,, in that order,,, software adjusts are the last ones to do, because if you dont,, it all gets out of whack, and you end up adjusting errors, so to speak,,

every time I have changed something ALA, polarisers, I have had to go back to square one and adjust all over again..

that is how much effect just changing polars has,,

I know this sounds all sort of easy,, but I have been on a very long trail, of demystifying,,, lamps/spectrums/lcd panels/CF filters/polars/triplets/ and the final linch pin,, was three days ago,, """""THE FRESSIE"""" which seems to have gone unoticed,,, its been EVO'ed buried

and even after all this,, I still only know 15% of the knowledge

ok here is std polar, then the SHC at 45 degrees

condensor side is std polar as per 3dlens

now the cam and settings where very fixed,,, also lots of daylight in room

ummmmm also this is with std LL lens 320mm FL and field fress of 330mm,,, the PRO lens is going back to anakin today,, so now back to old stuff

Click to view attachment

Click to view attachment

also notice the focus too,, bit interesting how polar effect it as well !!!!!!

Yes there is definitely a noticeable difference! What were the original specs of that panel, and how does the 90 degree orientation compare?

One thing semi-related but a bit OT.. I noticed you said you use 330mm fl field fresnel.. how do you like that compared to the 317mm fl fresnel?

questions questions:

Elken, where did you place the polars and how did you mount them for these specific pics?

Are you still using a polar mounted on the triplet that can be dialed in?

Are the polars fitted to fill the entire panel or are they smaller?

Thanks

Well I bit the bullet and ordered a half sheet of SHC polarizer. The small sheets were only big enough for 1 side of my 8.6" panel using the 90 degree config. So I ordered the 1/2 sheet which will be more than enough. I'll post my left over chunk if it seems that someone can use it for testing or replacement. Time will tell.

I may do a total replacement though my factory polars are in excellent shape with the ag removed, I would just like to increase my black contrast. Ahh the fun of perpetual tweeking. I'll try to post my before and afters.

Looking forward to your findings Sin. I'm really tempted to go with the full replacement both front and back on my 15" lcd. But I'm caught between doing this or going with 17" replacement panel. Will be keeping an eye on your work.

ummmm,, The polar is inside the triplet, nicely tucked and snuggled away from dust and dirt

the other is a quarter (panel) size near precondensor,,, floating on cotton threads,,, sometimes flutters away in the nice warm breeze,

elken, this is one of the issues that I was concerned about...does your fluttering polar cause any obvious visuals on projection?

Did you try having the polar butted up against the fresnel on the ungrooved side facing the lamp and did you find out if there were any descrepancies?

every posistion is fine, and even the suspended version, gently fluttering had no ill effects,, just so long as it did not rotate,, of course

as a side note,,, out of focal plane is the best for the polariser (on the condensor side)

now also for those using SHC,, on light side,,, dont destroy your orig polar if possible,,, just in case the image is too bright,, ala elevated blacks, becoming "luminous" as with your average domestic commercial PJ's,, but the whole greysacle shifts upwards,, giving complete clear greyscale seperation,,, IE--- no crushed blacks or crushed whites

if your blacks become too elevated,, due to high image brightness,, you can revert to either your orig polar or use the 3dlens one on the light engine side...

but using the SHC of trippy side is now an absolute success... with nil glowies or uneven blacks

Are you recommending only replacing the polar on one side then? Is the brightness an issue with both polars replaced when using the 150w ceramic blub?

Sinner7: Can you do a contrast measurement before and after you peel the polarizer? Is the 7" panel a low contrast panel ( 250 or 300 to 1) ?

You are the first to do this on a small panel and most of them just don’t look that good with the factory polarizer. Good luck.

Hey that’s a great idea, keeps the polar safe.

thanx dazzie wazzie,, twas your idea in first place,,, dah !

Did you end up putting an aperture in as well?

I can't believe no one has done this yet

umm for the moment i am back to a std lens,,, anakin is using his lens in his PJ now

I am so grateful for the loan of it from him, for the amount of time I had it,,

so till i get one for myself back to 330mm field fressie and 60mm optics

but fear not I still have a good image to play with,,, just had to move PJ into middle of lounge for non giant size screen,, heheh..

Actually my panel is 8.6", no matter, and it's contrast is 300:1. I'm satified with the brightness and color production, I'm really interested in better, darker 100% black. Maybe the SHC will work against my goal?

How would I go about measuring contrast?

Would it be black screen lumens / white screen lumens?

Or just black screen lumens before and after polar changes?

I don't yet have a lux meter, can I live with a cheapo from ebay? My projector budget is running dry.

After taking some preliminary test pictures yesterday I found it very hard to photo graph my black screen accurately. Any suggestions?

sure, anything is better than nothing
(30-40 bucks should get you something useful)

Last time I took a shot of a black screen I think it was a 15sec exposure (set manually), at Iso 100
Glowies showed up really well

For contrast measurements you ideally need to register at least 10lux on the black, you can do this by measuring closer to the triplet. Measure lux for a fully black then white screen (in the same spot).
Divide white lux by black lux to give full-on/full-off contrast.

(No need to bother with 9 square ANSI contrast as it is much too room dependant to be of any comparative value)

I don't suppose anybody has an extra section of SHC polar bear big enough to cover an 8" x 4.75" panel? I'm willing to pay...

Just ordered one for $35 with shipping from CA off of ebay.

So you suggest just measuring the center of the projected screen versus a 9 square grid average?

I'd prefer to keep it that simple. I'll do some more manual camera tinkering sometime to get some good pictures.

thanks

I'll probably have one soon, I just ordered a half sheet yesterday and should have extra. Keep in mind replacing only one will probably require you to cut a new one at 45 degrees, which requires a bigger piece. I will try to use a little as possible for mine and update my progress on this thread.

Thanks. Looks like 9" x 9" should do it, unless my geometry is even worse than I thought it was

For contrast measurement, yes it gives a reasonable ball-park figure
Averaging 9 squares is mainly useful for lumens output as it takes into account darker corners. But if you have the patience then you can do this for contrast measurements as well

i went to the post office today to pick this up. it really came friday but no one was home.
Click to view attachment

some before shots taken last night. 76 inch infocus screen ($35 w00t deal) i am home for vacation so this is in the basement, i didnt spend much time setting up the projector so the arc isnt perfectly centered and the very top is dim for some reason.

Click to view attachment

that looks familiar !!

morie is from the camera (nikon d70) all shots are:
2.5 seconds
f9
ISO 200
white bal manual (picture of white screen)
taken to left of projector on a tripod, remote fired

Click to view attachment

the global limit thing is driving me nuts so here is the last "before" shot.
wish me luck as i clean off the work bench

Click to view attachment

it's done. personally it (colors and contrast) looks the same, just clean. without all the scratches it was like looking at something completely different. i was hoping the black level and contrast at the lower exposure latitudes would be better, it's the same. probably because the panel was a relatively high contrast panel to begin with (600:1) the colors always seemed spectacular, dark scenes were always a problem. the "glowies" that were at the top corners are gone, but that might be because i centered the lamp a little better so black 0/0/0 is an even dim gray. alot of work for this panel. i should have went with the ASUS PM17TE but native widescreen just looked so appealing
oh well, there's my contribution. not that spectacular. something like a 350:1 low contrast panel would probably make a huge leap in performance with this though. perhaps someone with a small panel could use some donated scraps yoshuaspawn

Click to view attachment

But it is important to note that contrast is limited by the worst polarizer of your panel. Using a low quality polarizer and a high quality analyzer (front polarizer) is only going to go so far. But I agree, I figure 600:1 is not going to improve much even with both replaced.

Mark

At what angle did you have your new polarizer placed at? BTW, the pics of before and after of the DIY maiden certainly shows a difference in brightness unless that was a fault of the camera.

I also see a big difference in the pics. My polarizer just arrived today, the exact one you have. How far is yours positioned from the lcd?I was thinking of putting my on the rear fresnel, about half an inch away from the lcd. Any input?

the after pic is f 6.3 instead of f 9 so it looks brighter. the polar on the triplet is the same high contrast polarizer and both are oriented as the stock polars which were oriented 90 degrees.
i have the rear polar between the LCD frame and Fresnel so there is more than a quarter inch between the Fresnel and LCD

Here's my total documentation.

http://www.lumenlab.com/forums/index.php?s...6166&st=60#

Just an idea, but we had some glass tinted screen polarizers on our pcs at work, would this be another option?

Just took the polar off my panel, used syringe with water, and spray bottle, came up way better than the AG, now to get that privacy filter from work, and check if i've gotten back my 200 lcd

I have a question for the ppl that used SHC polar. I replaced the polar on one side of my panel(let's call it the bulb side). Would it make any difference if the SHC polar was on the triplet side?

Just wondering, as my black levels are suffering. I also don't want to flip the panel for nothing, as I already scratched the shc.

My flawless black levels (dark and even - no glowies at all) were only achieved replacing both polars with SHC, and split fresnels. The bulb side polar is mounted (directly touching) the groove side of the rear fresnel, the triplet side polar is mounted between the panel and front fresnel (about 4mm from panel glass). I couldn't get even-blacks with unsplit fresnels.

I just saw your results, and they look great. Tho I'm not sure if I'm willing to deal with the split fresnel headache. I might try adding a sheet to the triplet. Lose some brightness, but maybe gain better black levels.

All this makes me want to go commercial.

Yes, it's a lot of tinkering around with stuff to change your configuration. Just watch a few movies until you're motivated to make changes or can accept what you have. Half of this hobby for me has been experimenting and making changes towards improvement. I know how frustrating it can become trying to get it just right. Our setups just aren't precise like commercial optics, I found making everything movable is a lot easier to work with. Anyways, good luck. A commercial projector would be nice, and expensive but much less work.

When you start looking for a commercial with a real on screen 400 ANSI and a $100 lamp( OK you don't have to do that because there is none) and over ( not the same but over)1280x 768 rez they cost more than you think. Like $2K

Interesting thread, i think ive messed up the polarizer on the AG side of my panel, would the 17" replacement polarizer from 3Dlens.com work ?

i have a samsung syncmaster 740BF and as i was trying to remove the AG i accidently pulled up some of the polar.. so my question is basicly should take off the AG along with the polar attached to it and replace it with this?

http://www.3dlens.com/shop/17-inch-lcd-polarizer.php


here is my prob



Awesome results btw, im impressed and if i were in the states and not in sweden i'd buy a bunch of different polars to test but since shipping and import-tax becomes a bitch i cant afford to test.. wich is why im asking you guys if you think the product above would work -if so i'll order it.

First: don't buy polarizers form 3dlens, these are very low contrast ones, get the one from www.polarization.com

Second: if only that small piece is missing, just patch this damaged part with a new piece of polarizer, don't try to replace the whole thing. If you fit a new piece carefully, nobody will notice this damage, maybe the white screen will show it, but in the movies it will not be visible. Especially, that's just the very corner.

I would get some old LCD panel and try to recycle a piece of polarizer, often there are adhesive polarizers, that you can succesfully pull off.

Regards