Masking vs. Projection Luminosity

[pfelberg]

Hello.
I am getting somewhat unwanted results while using masks.
For a test, I printed a big logo and placed it on a wall.
Created the logo mask (all black with no BG) and saved as PNG.
Tested that as a layer mask and as well as a clip mask.
I was able to mask the layer, position the mask and fit to the logo. All images were projected inside the logo. Great!

But I am surprised that I could not entirely mask the projection light and I am getting a huge dim light square (like a light grey) projected on the wall as well. That´s not what I want. I want black (no light being projected) outside the mask.

What´s wrong, please?

thanks

Paulo

[pfelberg]

Just another test. Flatering the PNG and making a black&white mask ddin´t help so far.

[edwin]

Projectors are bad in projecting Black, what if you only project black?
Check your projectors setting to see wether you can adjust the Black levels.

[Joris]

Hey Paulo

Edwin is a man of very few words, and what he's trying to say is that a projector projects light (that's why it's called a projector ). So even when you're projecting a black screen, you're still projecting black light. This 'black light' is significantly brighter than true black, which is actually the absence of light. The better your projector is, the deeper the black will be, and some projectors have the option to set the black level. But even then, it will be visible if you look closely.

To check if this is indeed not a problem with your masks, simply eject all the clips and check the output. Most likely the same pale black square will be there. If this is the case, there is no way to make your projector not project any light in certain areas, aside from physically blocking parts of the lens.

If it is significantly darker than with your masks applied, please send us the masks and a clip at support[at]resolume[dot]com....

Joris

[John McGeoch]

I agree here - the black of any projector is one of the telling qualities in it`s specs and one of the key differences between cheap projectors and their more expensive fellows. Generally what are called home cinema projectors go for better blacks ( seen in the contrast ratio figures ) but are not as bright. Best projectors that we have for blacks are the Canon Xeed range which are LCOS based rather than LCD or DLP. - cheers JM

[pfelberg]

I agree here - the black of any projector is one of the telling qualities in it`s specs and one of the key differences between cheap projectors and their more expensive fellows. Generally what are called home cinema projectors go for better blacks ( seen in the contrast ratio figures ) but are not as bright. Best projectors that we have for blacks are the Canon Xeed range which are LCOS based rather than LCD or DLP. - cheers JM

I understood the main problem and realized that I needed a different projector than LCD. My masks were just ok.
I got a cheap DLP one and the magic was done. PERFECT!

tks