1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Howto Maximize black levels on ae300?

Discussion in 'Projectors, Screens & Video Processors' started by homeroids, Jun 13, 2003.

  1. homeroids

    homeroids
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Well, I am the proud owner of a brand new Pany PT-AE300e and was wondering if you could recommend settings, screen makeups (eg MDF board, Canvas, Goo paint, grey shade paints etc), that you have found which maximizes black levels without compromising brightness and colour range.

    I have a room that is 2.8m x 5.5m. The ae 300 projects on to the 2.8m wall at the moment and the wall is a slightly off white colour. I intend to experiment with a 2.15m by 1.22m MDF board and see what colour paint works best. I also intend to darken the side walls a lot, maybe with curtains because a lot of light is bouncing from the sides. There is also quite a light colour carpet and ceiling.

    The room is a great dimension for sound, being rectangular, having 1 entrance and just the one major window at the back.

    Any ideas on calibration settings and screen makeups to maximize black levels. Any advice would be appreciated.

    I am reasonably pleased with the contrast and black levels and realize they can be much better since I haven't optimized the room and screen yet.

    Thanks.
     
  2. Anders_UK

    Anders_UK
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    If you can black out and also optimise the whole colour of the room, this will enable you to sacrifice the illuminence of the screen and increase your black level by using a ND filter.

    A good way if you can afford the drop in Luminence.
     
  3. Mr_Belowski

    Mr_Belowski
    Member

    Joined:
    Mar 20, 2003
    Messages:
    777
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    63
    Location:
    Loughborough
    Ratings:
    +281
    In my HT room I pinned some black cloth to the ceiling in front of the wall where the image is projected. It's a low ceiling, so it really helped minimise light reflecting back onto the screen. Black curtains either side of the screen helped also.

    Basically, just remember that 'black' on your screen is only as dark as the ambient light falling on the screen, and focus on minimising that.

    It's really quite simple - take lots of little steps to reduce the amount of light hitting the screen that hasn't come directly from the projector.
     
  4. Anders_UK

    Anders_UK
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Not stictly true there Mr Belowski..although the steps you have taken are wise in that they will reduce the ambient light levels.

    But the black on your screen is not only as dark as the light falling on it, it is an inherent performance characteristic of the projector providing the image. The only way to reduce this to nearer a CRT level is to filter the ILLUMINENCE, either by controling the internal aperture or external methods such as neutral density filters.

    The rest is just common sense to optimise your kit.
     
  5. Mr_Belowski

    Mr_Belowski
    Member

    Joined:
    Mar 20, 2003
    Messages:
    777
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    63
    Location:
    Loughborough
    Ratings:
    +281
    Of course you're right Anders. I should have said that the black level is the ambient light + the light hitting that part of the screen from the projector.

    I stand corrected. Although there is a suprising amount of ambient light bouncing around even in a light-controlled room. I was very happy with darker black levels and extra shadow detail after taking those steps with my (now dead) Sanyo Z1 :)
     
  6. John_N

    John_N
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    You can get fantastic black levels if you turn off the projector.:laugh:

    Once you are past a certain point, you are not going to be able to improve the contrast of the image. The contrast of the image (ie the ratio between black level and white level) is more important than the absolute black level per se because of the nature of your eyes.

    Adding a filter and reducing the light output of the projector will achieve nothing worthwhile - the blacks get darker, the whites get darker and the dynamic range of the whole image gets compressed so you will find it harder to discern detail. It's rather like saying you can eliminate tape hiss on a recording by putting your hands over your ears. Sure you lose the hiss, but you lose the stuff you want to hear as well.

    If you wanted to reduce the ambient light bouncing around in a light controlled room, best way is to have the room a lot bigger! Given that we don't have that option, you could try lining the walls with a rough dark material - black carpet or black "egg crates" - anything that will reduce the efficiency of the reflection mechanism since the more times a photon changes direction before it reaches your eyes, the less energy it will have.

    To be honest I would focus on enjoying the movie. :)
    J
     
  7. Anders_UK

    Anders_UK
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    You don't effect dynamic range at all!! You effect the light levels between the 0 and 255 and the luminence of each step. If you choose a dense filter then sure your image will suffer, but a 0.1 or even 0.125 would be OK.

    Try and trick your eyes by putting a black border around the image and increase perceived contast of your image!!
     
  8. homeroids

    homeroids
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    What i've have tried so far is to reduce the picture size first. The picture was literally as wide as the wall it was being projected on. I could not make it smaller at the time due to the short throw lense on the Pany and the fact it was on a shelf behind the couch.

    I moved the projector to in front of the couch. This also allowed me to place the projector at a much more sensible height from the floor. Before it was mid-room level. Now, it is about 3.5 feet off the ground. This allowed for me NOT to use any horizontal or keystone adjustments. That resulted in a clearer picture. I then had some 1.2meter wide black cloth, 3m long. I placed it on the wall to the right of the picture for a test. All up, black levels were finally saturated enough, brightness (or contrast) increased due to the more reasonable diagonal size of the picture coming down to about 2.6m. Since the picture was less closer to the walls, there was less light bouncing. It all made a mark difference, and considering it's on a wall that can only be classed as second best (since it is quite heavily textured and a bad off white colour), I'm now quite impressed. Can't wait to get the screen together. With the black border on the screen (I intend to make it adjustable for 1:2.35) and maximum control of reflected/ambient light I'll be as happy as a pig in **** :).
     
  9. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,053
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,130
    Video intensity range isn't a linear response and neither are your eyes. By adding a filter you will drop the black point of the projector and there will be some loss to the whitepoint. However there are fewer intensity variations towards peak white ( historically designed in as the human visual system is better at detecting intensity variations in the lower part of the grayscale ( ie from black to the midtones).

    As long at the drop in overall intensity isn't enough to overly compromise the display of a full video intensity range ( which is pretty measly to be honest and most lamp projectors are if anything overly bright with regard to peak white point).

    Additionally the use of coloured filters with reference to certain projectors can also result in less dramatic overall drop of the whitepoint whilst stilll lowering the black point an appreciable amount. Although its likely to produce some colour innacuracy this may not be too problematic or indeed any less correct than what the projector is initially capable of with regard to colour depiction.
     
  10. John_N

    John_N
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Anders:

    Yes you are right, the dynamic range will be the same;

    if dynamic ranges are r1 and r2 and A = white level, B-black level and y = attenation of the filter we have:

    r1 = 10 Log (A / B)

    now add filter such that A = yA and B = yB

    r2 = 10 log (yA / yB )

    R1/R2 = 10 Log (A/B) / 10 log (yA / yB)

    = (log A - log B) / (log yA - log yB)

    = (log A - log B) / (log Y + log A - log Y - log B)

    = 1


    However, I also accept Mr D's argument about your eyes logarithmic response which means % changes in the greyscale near white are harder to spot because the steps in the greyscale at "white" are much bigger than the steps in the greyscale at "black".

    Maybe there is a happy medium where an ND filter can add value by reducing black level.

    I personally use a CC30R filter on my system because of the nature of the HS10 optics and do find that gives an improvement once the unit is calibrated.

    J
     
  11. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,053
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,130
    I wouldn't exactly say that the human visual visual system itself has a logarythmic response characteristic just that its easier for human beings to perceive intensity change in the mid to lower regions than towards peak areas. Its a small distinction but ...
     
  12. John_N

    John_N
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Hi Keith.

    Let us say then that the HVS appears to have a logarithmic response to brightness levels. If you search for "human visual system" and "logarithmic response" you will get a plethora of hits. Of course the term logarithmic is used very broadly. Are we talking about log to the 10 or log to the 8 or log to the 'e' for example? There is no way of telling. The only thing we do know is that the HVS response is non-linear and the curve seems to mirror a log curve in subjective tests.

    I'm not sure exactly what happens in the HVS as you move the overall brightness of your environment up and down but an intelligent guess would be: Obviously in a super-bright environment, your visual system will saturate and you will not be able to perceive detail. Likewise in a very dark environment. But in the middle I suspect that the eye will "auto balance" and will calibrate itself such that the brightest white object in the scene (within reason) is preceived as "white" and the brightness response below that will fall as some segment of the log curve. This is obviously what happens since it allows us to perceive a poorly lit (by comparison) white screen as "black" in a projection system.

    Not sure what point you are trying to make I'm afraid. Maybe I'm just being obtuse. :)
     
  13. theritz

    theritz
    Active Member

    Joined:
    Aug 17, 2002
    Messages:
    2,451
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Ireland
    Ratings:
    +27
    Homeroids,

    going back to your original question, a poster on avsforum with an AE300 which has been calibrated by an ISF guy has details in this thread - you may find some suggested settings there - the "before" and "after" pictures are enough to convince of the benefit of proper calibration.


    All the best,


    Sean G.
     
  14. homeroids

    homeroids
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Thanks heaps for that link. Just what I've been looking for. Cheers.
     
  15. theritz

    theritz
    Active Member

    Joined:
    Aug 17, 2002
    Messages:
    2,451
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Ireland
    Ratings:
    +27
    No problem, I was seriously impressed by the effect that the calibration had on that guy's projector - hope you get decent results - come back to this thread and let us know how you get on.

    All the best,

    Sean G.
     
  16. homeroids

    homeroids
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Oh, forgot to mention. I completed making my screen last night. It's simply a 2160mm x 1220mm, 3mm thick MDF board braced with rear MDF framing. It has 1 unit of black tint into 1 litre of Matt white, painted on the surface. A 1.5cm matt black edge has also been applied. The end result was beyond my expectations. I may experiment with other shades or possibly try getting some Goo paint.

    Having the image projected onto a contained screen adds to the viewing experience more than I can put into words. Walls simply don't cut it IHMO :). Plus the satisfaction of a DIY screen is most fullfilling. It cost me $70.00AU all up to make.

    Thanks for all the advice. Now I gotta try different calibrations.
     
  17. Bert Coules

    Bert Coules
    Well-known Member

    Joined:
    Mar 17, 2002
    Messages:
    2,999
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Ratings:
    +119
    The technicalities of this thread are somewhat over my head, but I do have one question regarding black levels.

    Am I imagining it, or is the black graphic "4" in the animated E4 channel ident logo considerably blacker than most blacks (so to speak)? Perhaps it's due to it being closely surrounded by much brighter images, perhaps it's some clever computer-graphic tweak, but to my eyes that "4" achieves a deep, even blackness that nothing else I see on screen can approach.

    Or perhaps it's just me.

    Bert
    www.bertcoules.co.uk
     
  18. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,053
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,130
    I would have thought its the surrounding brightness Bert .
     

Share This Page

Loading...