This kind of gradient is exactly what I have used for testing. It's
simple to build in After Effects using the ramp effect. I'll see if I
can upload a tiff to the files area of the list.
If you don't have a 10-bit CRT monitor, then you can examine this test
file in After Effects. You would need to be in a 16-bit+ project and be
zoomed up to 100%. The ramp value is equal to the x-value as you go
from left to right. If it has retained all 10-bits, then it will change
smoothly -- every increment in x will correspond to a change in the ramp
of 1. If it has been truncated to 8 bits, it will repeat the same value
4 times, before jumping up by 4.
Cheers,
--Michael
On 11-04-10 10:28 PM, nat jencks wrote:
> This will work OK, but the problem is if you create a gradient in photoshop, the gradient values don't map linearly from 0 to 1024.
>
> What would be very nice is a test patern which progressed, with 10bit values from 0,1,2,3, and so on to 1024.
>
> when when you view this on a 10-bit histogram thats 1024 wide, if your 10-bit you will see a solid horizontal, but if its 8-bit you will see the notches cut out.
> Or, if you have a 10-bit display and 10bit output and app that displays 10-bit properly you can see the difference between 10-bit and 8 bit gradient visually.
>
> A while ago I posted to this forum asking if anyone had a gradient like the one I described above, but no joy.
>
> good luck!
>
> -N
>
> On Apr 11, 2011, at 1:09 AM, johnrobmoore wrote:
>
>> So if I go into photoshop and make a black to white gradient if I save it as 10 bit that should work, correct? Too bad only CRTs assure no banding. Wonder if Sony is going to let me put that signal up on their new BVM replacement OLED monitors to check? This is starting to sound fun.
>>
>> --- In Avid-L2@yahoogroups.com, Bogdan Grigoresco<bogdan_grigorescu@...> wrote:
>>> horizontal B/W ramp with 1024 levels;
>>> make sure you test on a 10bit monitor(preferably CRT), otherwise banding may occur even with 10bit signals.
>>>
>>> cheers,
>>> Bogdan Grigoresco
>>> www.finale.tv
>>>
>>> --- On Mon, 4/11/11, johnrobmoore<bigfish@...> wrote:
>>>
>>> From: johnrobmoore<bigfish@...>
>>> Subject: [Avid-L2] Re: RGB QT export
>>> To: Avid-L2@yahoogroups.com
>>> Date: Monday, April 11, 2011, 7:10 AM
>>>
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>>> What is the proper method to test whether a file is 8 o10 bit? From this thread just because the inspector window say trillions how do you know the bits aten't getting truncated? Is there a specific test pattern to use etc...?
>>>
>>>
>>>
>>> --- In Avid-L2@yahoogroups.com, Michael Brockington<brocking@> wrote:
>>>
>>>> It's also worth mentioning that the same problem exists going in the
>>>> other direction.
>>>> If you export a 10-bit uncompressed material from the Avid using
>>>> same-as-source, you get a 10-bit quicktime. Testing will confirm it
>>>> really is 10-bit. But if you bring this into After Effects it shows up
>>>> as a footage item with only "Millions of Colours" and pixel values are
>>>> truncated to 8 bits.
>>>> Cheers,
>>>> --Michael
>>>> On 11-04-10 2:54 PM, Chris wrote:
>>>>> So Michael, if I read this right you are saying there is no way to any
>>>>> sort of QuickTime out of after effects for Avid import and stay 10 bit.
>>>>> Correct?
>>>>> Wow! Is this an Adobe or Avid problem (codec)?
>>>>> Chris Magid
>>>>> RTVF
>>>>> Office- 214 350 7212
>>>>> Cell---- 214 766 7212
>>>>> On Apr 10, 2011, at 1:56 PM, Michael Brockington<brocking@
>>>>> <mailto:brocking%40sfu.ca>> wrote:
>>>>>> Hi Nigel:
>>>>>> When I was looking into this a few months ago, Avid confirmed that
>>>>>> all third-party 10-bit codecs were truncated to 8 bit on both import
>>>>> and
>>>>>> export. With quicktime, the only way to preserve 10 bits in and out was
>>>>>> through fast-import of Avid-codec quicktimes and Same-as-source
>>>>>> exports. The other option was to use 16-bit TIFF file sequences, which
>>>>>> was what worked best for my circumstances. I am currently working on
>>>>>> 5.0.3.x, and that release stills seems to truncate in the same way.
>>>>>> In terms of confirming whether your export is 10-bit or not, you
>>>>>> could bring your clips into After Effects and check what it reports
>>>>> when
>>>>>> you select the item in the footage window. It will identify 10-bit
>>>>>> footage as having Trillions of Colours (vs Millions for 8-bit.)
>>>>>> However, this won't show you if your footage has been truncated to 8
>>>>>> bits within the 10-bit range. You would need to do some testing with
>>>>>> test patterns to confirm that. The other problem with After Effects, is
>>>>>> it doesn't seem to recognize Avid's 10-bit codecs (AvidPacked and
>>>>>> RGBPacked) as having 10 bits, only 8. One reason why TIFF sequences
>>>>>> work better for me for 10-bit file exchange.
>>>>>> Cheers,
>>>>>> --Michael
>>>>>> On 11-04-10 7:37 AM, Nigel Gourley wrote:
>>>>>>> So we AMA to 4:4:4 prores QT and then want to export as RGB
>>>>>>> uncompressed QT.
>>>>>>> This all works except I wanted to confirm it was actually a 10 bit
>>>>>>> file and
>>>>>>> not 8 bit. How do we do this.. We have used mediainfo usually for
>>>>>>> finding a
>>>>>>> file spec but while it gives bits for some formats it doesn't for
>>>>> others
>>>>>>> including prores..
>>>>>>> How can we confirm it's a 10 bit file if indeed it is?
>>>>>>> Thanks
>>>>>>> N
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