Manual - Holdan.eu

Y
Y
Perfect
alignment – your
red and green
vertical lines
should overlap
to produce
yellow ones.
12.10 Gamma correction
By now you should have two perfectly aligned projectors, but possibly with a
brighter than normal overlap. This is most probably because a projector’s
luminance is not perfectly linear and therefore will need to have what’s called
‘gamma correction’ applied.
Gamma correction is available within the same ‘Adjust keyers’ menu as the
other adjustments. You will need to adjust both output channels gamma
correction to be the same, unless you have non-matching projectors.
To change gamma correction:
1. Go into the ‘Adjust keyers’ menu.
2. For Output 1 (1A), change ‘E.blnd gamma’ (the first number) until the
brighter area starts to dim – note the number required for this.
3. For Output 2 (2B), change ‘E.blnd gamma’ (the first number) to the
same gamma value as per above.
4. Repeat steps 2 and 3, changing up or down as necessary until the
bright patch has disappeared.
The 2 nd number in the ‘E.blnd gamma’ is for where you have projectors
stacked vertically – e.g. for a 2x2 edge blend arrangement. The 1 st number
adjust the horizontal blend’s gamma value, whereas the 2 nd controls the
vertical blend’s gamma value.
Note that it may not be possible to completely remove a bright patch – this is
because some projectors can not actually output completely black images,
with some light always leaking through. However, the next adjustment is
designed specifically for this.
12.11 Brightness compensation
If you find it impossible to completely remove the centre overlap for all images
(i.e. dark images and bright images being projected), then two extra
compensation adjustments are provided to help with this.
The compensation is needed because most projectors cannot output pure
black – there’s always some light ‘leaking’ to the projection screen. Thus