Interference Patterns on Saturated graphics
by adam taylor
on
Jun 9, 2008 at 12:04:35 pm
I am having a problem with several company logo's that i need to use on a regular basis, but which all seem to display unpleasant interference patterns when viewed on a Broadcast monitor.
I work in 10bit Uncompressed Pal, and the graphics in question both incorporate a red body with white text. On the lcd monitor the images look great, but on a TV i can see what looks like bands /stripes of darker almost greenish noise. It makes a nice clean graphic look really second rate.
I have tried everything i can think of to cure the problem, including lowering the saturation, playing with all variations of the gamma, brightness, contrast. I have tried channel blurs, etc. I have even tried remaking the logos from scratch instead of relying on the clients (ubiquitous) crappy rez jpegs.
Any ideas how to solve this problem?
adam
Adam Taylor
Video Editor/Audio Mixer/ Compositor/Motion GFX/Barista
Character Options Ltd
Oldham, UK
Re: Interference Patterns on Saturated graphics by Jerry Hofmann on Jun 9, 2008 at 1:53:07 pm
Can you get an original version of the logo in a tiff or PNG or anything but a JPEG? Might be a lot better...
I don't particularly care for the the way JPEG images come out, and seems to me when I get a tiff of the same, it sure renders nicer.
Ya never know though, maybe if you open the JPEG in Photoshop and save it as an RGB tiff, things might improve?
Jerry
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Re: Interference Patterns on Saturated graphics by adam taylor on Jun 9, 2008 at 1:58:25 pm
I don't think thats it Jerry, as i avoid using jpgs if at all possible.
I have even remade the image from scratch, saving out to tiff (several different ways, also). I even created a red layer (cropped) in FCP and overlaid the white text and i still ended up with the interference pattern.
I think its something to do with how Pal handles saturated colours, but i am not sure how to approach the problem without drastically altering the look of corporate logos...which is usually frowned upon by the companies themselves (how very intolerant of them!!).
adam
Adam Taylor
Video Editor/Audio Mixer/ Compositor/Motion GFX/Barista
Character Options Ltd
Oldham, UK
Re: Interference Patterns on Saturated graphics by adam taylor on Jun 9, 2008 at 3:22:21 pm
version 6.0.3,
Kona 3
OSX 10.4.11
haven't tried it in 8bit....and no - not doing any scaling to this particular graphic. I have tried it at different scales and it seems to happen regardless!.
I gotta say, this has been noticeable on red/white logos since i got the kit 2 years ago, and after making initial investigations i kinda convinced myself to ignore it. Recently a job needed the logo bigger than normal which emphasized the issue and forceed me to look into it again.
I have a feeling this is one of those rare occurences where a PAL shortcoming rears its head, and will mean little to NTSC users. I remember a dim and distant seminar years ago when an engineer explained certain differences between the two systems, and i think what i'm seeing is one of those!
adam
Adam Taylor
Video Editor/Audio Mixer/ Compositor/Motion GFX/Barista
Character Options Ltd
Oldham, UK
Re: Interference Patterns on Saturated graphics by Jeremy Garchow on Jun 9, 2008 at 3:37:29 pm
[adam taylor]"haven't tried it in 8bit....and no - not doing any scaling to this particular graphic. I have tried it at different scales and it seems to happen regardless!. "
Duplicate your timeline, change the render settings to 8 bit and render that graphic. Does it help?
There used to be 10 bit render errors in FCP.
It could be PAL vs NTSC, but let's rule that out later.
Re: Interference Patterns on Saturated graphics by Michael Gissing on Jun 10, 2008 at 5:33:04 am
How are you feeding signal to the CRT monitor? Composite PAL on a CRT has horrible chroma crawl on red colours (note the PAL spelling).
If you are seeing it on an SDI or good component feed I am not sure what to suggest. A slight blur may soften the crawlies a bit. 8 bit may help but at the expense of all your pics.
Re: Interference Patterns on Saturated graphics by adam taylor on Jun 10, 2008 at 8:27:10 am
appreciate the spelling Michael!!
I'm using sdi all the way, into a JVC TM H1950C crt.
I tried rendering into various different codecs and the problem remained (Pro ResHQ actually made it a lot worse).
The only one that looked promising (at least unbtil i actually rendered was the "Graphic" codec. Once rendered it looked really grainy and unpleasant.
I don't have "sheer"so can't try it.
i wish i could post a screen grab, but as its only showing on the crt, that aint't possible.
I can say that the noise is not crawling in anyway, but looks more like echoing shadows that follow the shape of the edges of the red and white. With the graphic on a black background (to cancel any possible interference from other layers) there is a definite series of vertical shadows on the left hand side of the red box...much more obvious than on the other edges.
I'm now thinking its possibly the limitations of the crt that could be the cause!
adam
Adam Taylor
Video Editor/Audio Mixer/ Compositor/Motion GFX/Barista
Character Options Ltd
Oldham, UK
