Hey, I just thought to save a lot of the 'elders' on this forum the annoyance of answering questions over and over, I would start this thread.
I'll just give a simple explanation of the quality one may expect from a solid DIY Projector, feel free to add something. Or newbie's, please post your questions here (designated newbie thread) after searching ofcourse.
Quality One may expect:
Photos and movies of DIY projectors can help to understand the results one may expect, but they only help to an extent. Excelent pictures can make up for bad results, and bad pictures may ruin excelent results. So do explain what one can expect from a DIY Projector, I have made a quick explanation. Feel free to add/correct me.
DIY Projectors generally use single LCDs (Liquid Crystal Display). Quality of the LCD effects quality of the results, which is why people in the last months have gone from using ready made projection panels, such as the nView Spectra C, to laptop panels run by computers.
These LCDs have certain amounts of pixels on them which all become a color and make a picture. The more pixels and higher resolution, the more realistic and smooth a picture will be at high projections. The amount of pixels needed depends on the prefrence of the user. Some are satisfied with 640x480 (307,200 pixels) while others like myself prefer 1024x768 (786,432 pixels) minumum. The amount of pixels also affects the amount of screen-door effect that will be shown. Screen door effect is when pixels don't change color quickly enough, and so gives the effect of the pixels draging. Sort of like when you look through a screen door, hence the name. The more pixels, the smaller they are, which means the less screen door will be noticed.
LCDs also display certain amounts of colors. The more colors the closer the real life the results will be. 16-bit color or more is a recommended amount.
LCD display timing also is very important. The lower the seconds, the less blur and better results. I recommend 20ms or less.
Retail LCD projectors (most anyway) have one difference to DIY. Besides size of course. DIY projectors only use one single LCD which provides RGB color (Red Green Blue) which can mix to combine their millions of colours. Retail projectors however use three LCDs. One to handle the Red, one to handle the Green and one to handle the Blue. This makes little difference to the picture quality though, and the only reason I can see that this is done is because of Blacks. Now as we know, there is no way to have black light. Black light is no light. And so the blacks for your results depend on the amount of outside light in your room (which is why people recommend to have no other light, and also to paint the inside of the enclosure black so not to reflect and muddle the light), and the actual screen color, which is why many paint their screens a shade of grey. Using three LCDs however can produce Black on screen. By projecting Full blue and full greeen and full red on the same spot (requiring perfect alignment) makes black. This puts many people off DIY projectors. But what many don't realise is that theatre projectors do not project black. Which is why there is as little other light in the room as possible. And so if you look, the blacks are usually represented by a navy blue. And so if you don't mind cinemas, you don't mind DIY LCD projectors.
All that aside, quality depends on the size of the projected image, in relation to the amount of colors, in relation to the response time, in relation to the amount of pixels.
Get a high grade LCD in your setup and you should be right.
OOP! ran outta time. someone else can continue.
Hope this helps
I'll just give a simple explanation of the quality one may expect from a solid DIY Projector, feel free to add something. Or newbie's, please post your questions here (designated newbie thread) after searching ofcourse.
Quality One may expect:
Photos and movies of DIY projectors can help to understand the results one may expect, but they only help to an extent. Excelent pictures can make up for bad results, and bad pictures may ruin excelent results. So do explain what one can expect from a DIY Projector, I have made a quick explanation. Feel free to add/correct me.
DIY Projectors generally use single LCDs (Liquid Crystal Display). Quality of the LCD effects quality of the results, which is why people in the last months have gone from using ready made projection panels, such as the nView Spectra C, to laptop panels run by computers.
These LCDs have certain amounts of pixels on them which all become a color and make a picture. The more pixels and higher resolution, the more realistic and smooth a picture will be at high projections. The amount of pixels needed depends on the prefrence of the user. Some are satisfied with 640x480 (307,200 pixels) while others like myself prefer 1024x768 (786,432 pixels) minumum. The amount of pixels also affects the amount of screen-door effect that will be shown. Screen door effect is when pixels don't change color quickly enough, and so gives the effect of the pixels draging. Sort of like when you look through a screen door, hence the name. The more pixels, the smaller they are, which means the less screen door will be noticed.
LCDs also display certain amounts of colors. The more colors the closer the real life the results will be. 16-bit color or more is a recommended amount.
LCD display timing also is very important. The lower the seconds, the less blur and better results. I recommend 20ms or less.
Retail LCD projectors (most anyway) have one difference to DIY. Besides size of course. DIY projectors only use one single LCD which provides RGB color (Red Green Blue) which can mix to combine their millions of colours. Retail projectors however use three LCDs. One to handle the Red, one to handle the Green and one to handle the Blue. This makes little difference to the picture quality though, and the only reason I can see that this is done is because of Blacks. Now as we know, there is no way to have black light. Black light is no light. And so the blacks for your results depend on the amount of outside light in your room (which is why people recommend to have no other light, and also to paint the inside of the enclosure black so not to reflect and muddle the light), and the actual screen color, which is why many paint their screens a shade of grey. Using three LCDs however can produce Black on screen. By projecting Full blue and full greeen and full red on the same spot (requiring perfect alignment) makes black. This puts many people off DIY projectors. But what many don't realise is that theatre projectors do not project black. Which is why there is as little other light in the room as possible. And so if you look, the blacks are usually represented by a navy blue. And so if you don't mind cinemas, you don't mind DIY LCD projectors.
All that aside, quality depends on the size of the projected image, in relation to the amount of colors, in relation to the response time, in relation to the amount of pixels.
Get a high grade LCD in your setup and you should be right.
OOP! ran outta time. someone else can continue.
Hope this helps
Screendoor effect is simply being able to see every pixel on screen... not pixels dragging.
Example: if an lcd has 85 pixels per inch... and you blow up the picture 10 times it's original size... you'll be able to see those 85 pixels because the inch is now 10 inches on screen.
Example: if an lcd has 85 pixels per inch... and you blow up the picture 10 times it's original size... you'll be able to see those 85 pixels because the inch is now 10 inches on screen.
Morien said:
That is how a white color is made, not black. Black is just no light. Three LCD:s can help in eliminating the screendoor but not in improving black level, though it may be that monochrome LCD:s are easier to manufacture to block the light coming from the light source completely (or almost).
jcbklyny,
Uh... Yeah I know...
I was just, uh... pointing out a fact to all the newbies. That uh... everyone makes mistakes and says 'incorrect' things. So don't be embarrased if you do too.
...
Covered that one up pretty nicely...
Point still holds true, the more pixels, the less obvious it will be at a certain size.
Also, if pixel amount of your LCD is a problem, and all you really watch on it is 16:9 broadcasts, you can make an anamorphic lens. What this does, is get a 4:3 image, (which anamorphic dvds are, they are just resized by the dvd player, which can be stopped) and then narrow the beam to be 16:9, which squashes the image and makes pixels even less obvious. This is a good idea even for higher pixel LCDs as it makes a 4:3 image 16:9 (widescreen) and better quality. And if you are running it off a PC, then you can get DVD software, such as Theatretek which will automatically resize 4:3 programs to be shown as 4:3 through an anamorphic lens.
See http://home.c2i.net/ahustvedt/ or the DIY Anamorphic lens thread on this forum for information on building your own Anamorphic lens
and
see http://www.avsforum.com/ for more info on using your PC as a home theatre component (then called a HTPC, Home Theatre Personal Computer)
Hope this helps. And once again, I'm pretty rushed nowdays whenever I post, so feel free to correct me on anything I say.
Uh... Yeah I know...
I was just, uh... pointing out a fact to all the newbies. That uh... everyone makes mistakes and says 'incorrect' things. So don't be embarrased if you do too.
...
Covered that one up pretty nicely...
Point still holds true, the more pixels, the less obvious it will be at a certain size.
Also, if pixel amount of your LCD is a problem, and all you really watch on it is 16:9 broadcasts, you can make an anamorphic lens. What this does, is get a 4:3 image, (which anamorphic dvds are, they are just resized by the dvd player, which can be stopped) and then narrow the beam to be 16:9, which squashes the image and makes pixels even less obvious. This is a good idea even for higher pixel LCDs as it makes a 4:3 image 16:9 (widescreen) and better quality. And if you are running it off a PC, then you can get DVD software, such as Theatretek which will automatically resize 4:3 programs to be shown as 4:3 through an anamorphic lens.
See http://home.c2i.net/ahustvedt/ or the DIY Anamorphic lens thread on this forum for information on building your own Anamorphic lens
and
see http://www.avsforum.com/ for more info on using your PC as a home theatre component (then called a HTPC, Home Theatre Personal Computer)
Hope this helps. And once again, I'm pretty rushed nowdays whenever I post, so feel free to correct me on anything I say.
Re: Re: A Newbie introduction to DIY LCD Projectors.
When it's to do with a projected image, white is made by no color being on the lcd. That way light can pass through undestirbed keeping it's original color. When Full Red and Full Green and Full Blue light are shon on the same spot, black is formed.
On single RGB lcds, black does block the light from coming through and so cannot be projected, so the black color is left up to lighting conditions and the screen color, but Red, Green and Blue are projectable, and combine to make black.
Gee guys. This is a thread to introduce newbies without annoying people by asking the same question over and over. Your not doing much for my credability here.
mhelin said:
When it's to do with a projected image, white is made by no color being on the lcd. That way light can pass through undestirbed keeping it's original color. When Full Red and Full Green and Full Blue light are shon on the same spot, black is formed.
On single RGB lcds, black does block the light from coming through and so cannot be projected, so the black color is left up to lighting conditions and the screen color, but Red, Green and Blue are projectable, and combine to make black.
Gee guys. This is a thread to introduce newbies without annoying people by asking the same question over and over. Your not doing much for my credability here.
... then I'll say no more 🙂
But Morien, you have to realize that all the info new people need is already here. They just have to search for it.
But Morien, you have to realize that all the info new people need is already here. They just have to search for it.
True, but how many people search??? 🙂 hehe
just like on the forums at forums.maxima.org.... we have a
special sticky that answers the most common questions newbies ask 🙂
though all the info could also be found by searching... 😀 it's super easy to just click a thread for all the info...
cool 😀
just like on the forums at forums.maxima.org.... we have a
special sticky that answers the most common questions newbies ask 🙂
though all the info could also be found by searching... 😀 it's super easy to just click a thread for all the info...
cool 😀
morien
Yeah i search too, infact for 2 months i read most if not all of the posts on here before i even made a post lol, its a shame others dont but any way u get that lol good idea anyway morien starting this thread lets just hope it works, and as for the 3 lcd projectors i always thought they use that idea to have a closer colour matching and to throw out more light with less distortion in the image and u can project black but im sure it is not what the red, green and blue are for but i bet it would help the black level in the image as there are 3 lcd's to block the light rather than 1, anyway im not going to argue about it lol keep up the good work guys and happy diy
Trev
Yeah i search too, infact for 2 months i read most if not all of the posts on here before i even made a post lol, its a shame others dont but any way u get that lol good idea anyway morien starting this thread lets just hope it works, and as for the 3 lcd projectors i always thought they use that idea to have a closer colour matching and to throw out more light with less distortion in the image and u can project black but im sure it is not what the red, green and blue are for but i bet it would help the black level in the image as there are 3 lcd's to block the light rather than 1, anyway im not going to argue about it lol keep up the good work guys and happy diy
Trev
I managed to extend the ribbon to my eizo l 360 15" lcd and make it work for projection.For the moment i use one HQI-TS 150W/NDL Osram lamp and there is not so much brightness.I do not have any problem with heat.I have placed the lcd on top of the fresnel.Today i bought the HQI-TS 250W/NDL with the rest stuff for it to light and i wonder will i have to put an extra glass now to keep the heat away because this lamp is more hot?doesn't the fresnel and the funs keep the the temp down?I know i have a glass frame left on the 3m OHP i took apart,sould i use it?Where should i place it?
There is also something else i would like to ask,are the optics of the 1708 3m OHP ok for pj or i must buy something else?My picture look like air is blowing,if you know what i mean.When something white is next to something black you see the white fade in the black.Moving the objective lense helps to the half of the screen.I hope someone will help thanx.
There is also something else i would like to ask,are the optics of the 1708 3m OHP ok for pj or i must buy something else?My picture look like air is blowing,if you know what i mean.When something white is next to something black you see the white fade in the black.Moving the objective lense helps to the half of the screen.I hope someone will help thanx.
Actually... In conmercial projectors the lcds are monocrome, meaning they are "black and white" not color. The beam of "white" light going into the projector from the lamp gets filtered through special glass lens that split the beam into colors... blue, green and red. This colored light is then passed though the LCDs. The LCDs then add the black by turning on and off each pixel. Whatever is white, the lcd is transparent but when it needs to be black the lcd turns off the pixel to make it dark and block light. Contrast is how dark the pixel can get to block the most light. The darker the pixel the better the contrast.
White light is made of red, blue and green light. You can check this by getting three flash lights and putting colored filter paper and shining them to the same spot, white light. There is no such thing as black light because black or dark is an absence of light.
ap0
White light is made of red, blue and green light. You can check this by getting three flash lights and putting colored filter paper and shining them to the same spot, white light. There is no such thing as black light because black or dark is an absence of light.
ap0
No way for real??????????? Danggggggg.... look like I just got a new wrinkle in my brain just now, learn something new everyday Sweet , L8er
black light
u can buy a black light but its uv lol just thought i would add that to be a smart u know what lol
u can buy a black light but its uv lol just thought i would add that to be a smart u know what lol
There is a 3lcd projector at my school, and I have always examined it since DIY Projectors have warped my mind (i even look for projection faults in cinemas now, and with diy i can see many.)
What I have noticed is that the results do infact seem to produce black light by having 3 lcds. One to handle the blue, one to handle to green and one to handle the red. How do I know that it is not my eyes tricking me? Because the screens aren't cut to fit the picture, and so there is much unused space which isn't touched by the projector. Those parts are actually lighter than some of where the projector touches, which is made very obvious when the xp startup screen comes up and there is a direct comparison for me. When questioning that, I was told to think of it in relation to the 3 lcds and how black would be made (never being told a direct answer, damn teacher) and that led to me realise and I was told i was correct.
To answer some people.
Yes, I do realise that you should search the forums before asking questions, I even recommend it, but the problem is that people don't, and all that can be done besides ignoring them, is to supply a solution, which I have tried to do with this thread.
WMT, if someone could answer your problem that will be great, but I will try to answer some of your questions. You really do need a very bright bulb (brightness rated by lumens, generally 10,000 lumens is enough, for me anyway (only about 10% makes it past the lcd and becomes ANSI lumens)), recommended lighting is metal halide. You should also get as close to pure white as possible.
The fresnal does reduce heat, very slightly though, and it is not a recommended heat prevention technique as that should be protected from the heat. People generally use two types of fans to help cool the projector, fans to blow air in, and fans to blow air out, also glass is used however it does reduce your brightness. I'd say you should place the glass between the fresnal and lcd, like what it is in the original overhead design, others may think different ? I'm not sure about your last question however.
ap0the0sis, 'There is no such thing as black light because black or dark is an absence of light.' - My point exactly.
ace3000_1, always has to be a smart **** eh. 🙂 I've seen those in catalogues. Not entirley sure on how they work though.
What I have noticed is that the results do infact seem to produce black light by having 3 lcds. One to handle the blue, one to handle to green and one to handle the red. How do I know that it is not my eyes tricking me? Because the screens aren't cut to fit the picture, and so there is much unused space which isn't touched by the projector. Those parts are actually lighter than some of where the projector touches, which is made very obvious when the xp startup screen comes up and there is a direct comparison for me. When questioning that, I was told to think of it in relation to the 3 lcds and how black would be made (never being told a direct answer, damn teacher) and that led to me realise and I was told i was correct.
To answer some people.
Yes, I do realise that you should search the forums before asking questions, I even recommend it, but the problem is that people don't, and all that can be done besides ignoring them, is to supply a solution, which I have tried to do with this thread.
WMT, if someone could answer your problem that will be great, but I will try to answer some of your questions. You really do need a very bright bulb (brightness rated by lumens, generally 10,000 lumens is enough, for me anyway (only about 10% makes it past the lcd and becomes ANSI lumens)), recommended lighting is metal halide. You should also get as close to pure white as possible.
The fresnal does reduce heat, very slightly though, and it is not a recommended heat prevention technique as that should be protected from the heat. People generally use two types of fans to help cool the projector, fans to blow air in, and fans to blow air out, also glass is used however it does reduce your brightness. I'd say you should place the glass between the fresnal and lcd, like what it is in the original overhead design, others may think different ? I'm not sure about your last question however.
ap0the0sis, 'There is no such thing as black light because black or dark is an absence of light.' - My point exactly.
ace3000_1, always has to be a smart **** eh. 🙂 I've seen those in catalogues. Not entirley sure on how they work though.
Morien
a black light is just simply a fluro tube without the phoforus coating and with a black special uv coating so u can see the uv very slightly in the violet range because if u had no coating u wouldnt see anything as we can not see uv light, its the lights u see in the night clubs ect
a black light is just simply a fluro tube without the phoforus coating and with a black special uv coating so u can see the uv very slightly in the violet range because if u had no coating u wouldnt see anything as we can not see uv light, its the lights u see in the night clubs ect
Can you please elaborate again in more detail how an anamorphic lens takes the dvd signal and makes it sharper. My understanding was when you rent a dvd that has the original format such as 1.85:1 then that is what you will see. Therefore the default aspect ratio encoded is this. Yes you can zoom in to a 4:3 if your dvd can do that but that would be cropping the sides of the original image. If you are talking about taking a already formated for you tv dvd and stretching that to a 1.85:1 or 16:9 ratio with a anamorphic then this is no good either. Who wants fat distorted people and faces?
dracul,
Your missing the point of an anamorphic lens entirely.
All DVD material is encoded in 4:3 format. 16:9 is encoded in 4:3 and 4:3 is encoded in 4:3. The other widescreen ratios are 4:3 with borders.
The DVDs then send the player a message telling it to either leave it in 4:3 mode or to squash it to 16:9.
However, when you plan to use an anamorphic lens you will want to make 16:9 movies play in 4:3 again, this way there is no pixel loss. However, this gives the effect of Very tall video, which is where the anamorphic lens comes in. This then squashes the light output to be 16:9 again, which gives a sharper more detailed image as there are more pixels being displayed. It gives better quality than no anamorphic and setting the dvd player to play it as 16:9 as that reduces the pixels.
How 4:3 material would work, is the player should (i don't know about standalone, i use a htpc) add borders to the side of the image to make it remain 4:3 after it passes through the anamorphic lens. The problem with this however, is it reduces the amount of pixels for 4:3 images. So it's a trade off, better 16:9 and worse 4:3 or 4:3 letterbox and 4:3. Which is why they are for projectors, which are generally for Home Theatre (16:9 use).
If you don't understand then search the forum for a detailed explanation. Don't count on a reply from me though, this reply was my first post in about a year (I lost interest for the project due to lack of funds 🙁 )
Morien
Your missing the point of an anamorphic lens entirely.
All DVD material is encoded in 4:3 format. 16:9 is encoded in 4:3 and 4:3 is encoded in 4:3. The other widescreen ratios are 4:3 with borders.
The DVDs then send the player a message telling it to either leave it in 4:3 mode or to squash it to 16:9.
However, when you plan to use an anamorphic lens you will want to make 16:9 movies play in 4:3 again, this way there is no pixel loss. However, this gives the effect of Very tall video, which is where the anamorphic lens comes in. This then squashes the light output to be 16:9 again, which gives a sharper more detailed image as there are more pixels being displayed. It gives better quality than no anamorphic and setting the dvd player to play it as 16:9 as that reduces the pixels.
How 4:3 material would work, is the player should (i don't know about standalone, i use a htpc) add borders to the side of the image to make it remain 4:3 after it passes through the anamorphic lens. The problem with this however, is it reduces the amount of pixels for 4:3 images. So it's a trade off, better 16:9 and worse 4:3 or 4:3 letterbox and 4:3. Which is why they are for projectors, which are generally for Home Theatre (16:9 use).
If you don't understand then search the forum for a detailed explanation. Don't count on a reply from me though, this reply was my first post in about a year (I lost interest for the project due to lack of funds 🙁 )
Morien
hey guys,
commercial lcd projectors have 3 monochrome lcds as has already been estalished. however the red, green and blue is not created by special lens', it is created by reflecting off dichroic mirrors, which you see on halogen downlights, they reflect only a certain colour on different angles.
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Jake
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commercial lcd projectors have 3 monochrome lcds as has already been estalished. however the red, green and blue is not created by special lens', it is created by reflecting off dichroic mirrors, which you see on halogen downlights, they reflect only a certain colour on different angles.
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Jake
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- Status
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