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Discussion Starter · #1,861 ·
IIRC your older advice was to run a gamma+color autocal every long while (say 500 hours or so), and to run color only autocal's in between, say every couple hundred hours. So now that you are saying you do not run any color only autocal, does that mean that you no longer feel its worth pulling out the meter in between to do a tune up with the color only? Or are you saying that at the time you do the gamma+color you just also redo that at the multiple iris positions? If so, why? IIRC running the gamma part all over again with each color calibration just wastes time, as it simply just overwrites the last gamma done (if all that's changing is the iris position).

Also - can you post how your grayscale looked after calibration but before your custom color profile was applied?
I do not run color only in between. I run a check with Calman from time to time, and when it looks like I need an Autocal (or when I need to open the iris) I run a gamma+color.

I have already advised that running color only for each iris settings was a waste of time unless you want the flexibility of being able to use any iris setting in a given mode. The instructions have been updated ages ago.

I'm in the process or running a new autocal because I have noticed that while the Spyder 5 was slightly more accurate than the Spyder 4 when facing the screen, it is significantly less accurate when facing the PJ, which is what matters with Autocal. Also, it seems to be responsible for my brightness drop (I'm back to 130nits in low lamp with the Spyder 4).

I'll post details when I'm done.
 

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Discussion Starter · #1,863 ·
Improving BT2020 Autocal results with a custom profile

So I've done lots of tests today and here are my results:

1) The reference color profile on our models is the same as DCI-P3-F, so there is no need to use one slot with DCI-P3F.
2) Instead of calculating the new BT2020 targets from the rec-709 offsets as per Chad's procedure, it is possible to significantly improve the results in BT2020 by calculating specific offsets for the BT2020 profile using P3 targets (we can't use BT-2020 targets because our PJs can't reach BT2020, they reach 65-70% of BT2020 at best).

So here is the procedure I followed:

- I updated Chad's spreadsheet with DCI-P3 targets instead of Rec-709 target. This means that you can calculate offsets with the filter on and at the targets that matter most for current content, i.e. P3.
- I updated Chad's workflow so that it defaults to DCI-P3 / D65 / Power Gamma 2.2

Once you have followed Chad's procedure (or my slightly modified version) to calculate the rec-709 offsets and created the rec-709 custom profile to correct the meter errors at rec-709, load my DCI-P3 workflow, and use the gamut luminance layout to create the offsets for DCI-P3. To do this, do the following:

- In your HDR user preset, select Reference, 6500K, gamma normal on the projector in high lamp, iris fully open. This is important as this will give you the widest possible P3 gamut. Low lamp reaches a narrower gamut, so even if you use low lamp to calculate the offsets select high lamp, iris open. This will make sure that the errors are mostly meter errors and not too much native gamut limitations.
- Run a gamma 33 points+color autocal
- Open the DCI-P3 workflow and measure the current user mode (still on reference, 6500K, gamma normal, high lamp, iris fully open). This will give you the reference reading at various levels of luminance. Copy the RGBW xy just as you did for rec-709, and copy them in my updated DCI-P3 spreadsheet.
- Once all the RGBW data is copied, the speadsheet will give you your new targets for DCI-P3 and BT2020.
- If you want, create a custom profile for DCI-P3. There is little to no consumer content using this, so it's not necessary to do so. However, it is interesting to create one as you can then import and select the new DCI-P3 profile and compare the readings with the reference (non-custom-corrected) one. You should see significant improvements.
- Create a custom BT2020 profile using the new BT2020 targets. This is the profile you'll use for UHD Bluray HDR etc. It's the same as the one you created following Chad's procedure, except that it should give you improved results in BT2020.
- Open a BT2020 / D65 workflow, select the new BT2020 profile in the PJ, select P3 Sweeps (P3 within BT2020) with a normal gamma and check the results. You should notice a significant improvement.
- Select your custom gamma, set 100% white to D65 and measure your actual BT2020 calibration using the multiplier used in your selected Arve curve. Gamut and gamma/greyscale should be fairly close. I attach my final results.
- If you need to use a different setting than HDR High lamp / iris full open, run an autocal using reference/6500k/normal, then select the custom BT2020 profile, custom gamma and set WB to D65 at 100%. There is no need to recalculate a profile in low lamp, it would most likely lead to gamut shrinking.

I did more tests with my Spyder 5 / Spyder 4 and while the Spyder 5 is more accurate facing the screen, it's less accurate facing the projector, which leads to more (unnecessary) correction and a significant loss of brightness (118nits vs 132nits in low lamp HDR, 170nits vs 186nits in high lamp HDR, once fully calibrated to D65). So my last attempt at replacing my Spyder4 by a Spyder5 is over. The Spyder5 is going back as I would never use it given the brightness drop it causes.

Hope this helps. Not much time to follow up on this, but I'm sure those who are fluent in Autocal will pick up on this and will be able to help.

Following this new procedure, I get a color volume of around 98% of P3 in both low lamp and high lamp, so I might go on using low lamp unless I really need the extra pop. The fan noise and heat in high lamp is unpleasant, especially in summer!

Let us know if this improves your BT2020 results or not!
 

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Discussion Starter · #1,865 ·
Keep in mind Manni, the newer autocal software has the Spyder 5 only, so future models that you may want may not include support for the Spyder4. If you know you have a good sample, might be best to keep it for future use.
Thanks Kris, but this Spyder 5 isn't any better than the four others I tested. It's just that because Calman supports it, I was able to check it facing the screen, and I thought 2.8 dE on white isn't bad, as I remember my other S5s being 6-7 dE. My Spyder 4 had a dE of 5 facing the screen.

It's only after I ran an Autocal and noticed the 15% brightness dropped compared to my Spyder 4 that I did more checks. I then realized that the accuracy is reversed facing the PJ (which is all that counts for the Autocal). The 4 had a dE under 3 and the five around 7. Hence the huge drop in brightness, because the brightness loss caused by this over correction cannot be reclaimed, even with a custom profile.

At the end of the day, this one was no better than the other, and much worse than my s4. There is no way I'm keeping a Spyder 5 just in case I might use it one day if I know I won't use it with my current projector.

My understanding is that the new models support the i1pro2, which I'd much rather use although I have doubts they will be able to read the low end of gamma and the top end at the same time when facing the projector, even with the diffuser. The i1pro2 doesn't read accurately very low, and it caps at 1200nits, which is almost four times less than the Spyders, which are better than the i1pro2 in the low end and read up to 4000nits. If anyone has tried an autocal with the i1pro2, I'd love to get some feedback.

In any case, when/if I upgrade my PJ, which might not be for a couple of years, I'll get a meter if the i1pro2 doesn't do the job well. This Spyder 5 was just as bad as the others... I guess they have improved accuracy facing the screen at the expense of the accuracy facing the PJ. It's not my screen as it's very color neutral (Carada BW), so it has to be the meter.
 

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Reposting from the RS520 thread:

Does anyone know whether Xrite i1 Pro (Rev E) works with Autocal?
My understanding is that Rev E is basically Pro 2, but i'm not sure if it will be compatible with autocal since it specifically stats Pro 2.
 

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I'm so confused.
Anybody in Victoria Australia wanna swing by my place and give me a hand? :)
be ya best friend...
 

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The more i read this thread, the more confused i get and more questions i have.
I am hoping it will be much simpler when i plug it all in and give it a go.
 

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Reposting from the RS520 thread:

Does anyone know whether Xrite i1 Pro (Rev E) works with Autocal?
My understanding is that Rev E is basically Pro 2, but i'm not sure if it will be compatible with autocal since it specifically stats Pro 2.
AutoCal only works with Spyder5 for v6 & v7, and Spyder4 for lower version
i1Pro2 works with the latest version but that's a spectrophotometer
 

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AutoCal only works with Spyder5 for v6 & v7, and Spyder4 for lower version
i1Pro2 works with the latest version but that's a spectrophotometer
Yeah I understand that.
The question is, will an i1pro 1(rev E) works with autocal since it is supposed to be the same as ipro 2? OR do I have to buy one that specifically says i1pro 2 on the box.
 

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Yeah I understand that.
The question is, will an i1pro 1(rev E) works with autocal since it is supposed to be the same as ipro 2? OR do I have to buy one that specifically says i1pro 2 on the box.
If you have the i1Pro1, just try to connect to the autocal and if it could detect the meter, it might work.
 

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Discussion Starter · #1,877 · (Edited)
Yeah I understand that.
The question is, will an i1pro 1(rev E) works with autocal since it is supposed to be the same as ipro 2? OR do I have to buy one that specifically says i1pro 2 on the box.
If you have the i1Pro1, just try to connect to the autocal and if it could detect the meter, it might work.
The i1pro2 already has a very limited range, the i1pro revE is VERY unlikely to produce good results, even if it was detected. It's limited to around 300nits, vs 1200nits for the i1pro2 (vs 4000nits for the spyders). The i1pro2 is also more sensitive/reliable in the low end, and doesn't need a dark calibration as frequently as the i1pro.

Unless they use the i1pro2 as a spectro to profile another meter (which I don't think is the case), I wonder how the i1pro can do a 33 points gamma+color autocal. I'm not sure how the i1pro2 could achieve that, even with its extended range.

I have an i1pro2 but I don't have an rsx20 model, and the most recent software version that supports our models (V7) doesn't support the i1pro2, so I can't test it.

I haven't heard of anyone having tested the i1pro2 with the JVCs, so I'm very interested to hear some feedback, but I'm not convinced it will provide good results for gamma calibration. It should work great for color though. I might work for 9 point gamma.

[EDIT: I read the software manual for the latest version of the software for the RS4500 and it looks like when using the i1pro2, the meter is facing the screen, which is great as it takes the screen into account (the Spyder 5 is still used facing the PJ). This means that the 1200nits limitation if the i1pro2 isn't an issue, and even the 300nits limitation of the i1pro rev E wouldn't be for most projectors setups, but the low-end limitation of both of these meters still stands. The i1pro2 isn't used to profile the Spyder 5, but is used on its own. I wouldn't trust a gamma calibration with an i1pro below 30% white (I used to have one). I wouldn't trust the gamma calibration of an i1pro2 below 15% white, maybe 10% at best. So the i1pro2 might work with a 9 step gamma calibration, but I doubt a 20 or 33 steps would work. I don't believe an i1pro rev E stands a chance due to its limitation in the low end, even with 9 steps only. These are spectros, they are not meant to calibrate gamma, only to be users as reference meters to profile a colorimeter or to do a gamut calibration / above 30% white calibration]

Personally, if I didn't have an i1pro2 already and planned to use it for JVC Autocal of the new models exclusively, I would wait for some feedback before purchasing one.

Of course beware, the i1pro2 isn't supported with the models on topic in this thread (rsx00) or older models. It's only supported on the rsx20 line and the rs4500/Z1, along with the Spyder5. I don't know if the autocal has been fixed for the new line though, last time I heard it was broken.
 

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Can you tell me the cheapest way to generate hdr patterns for BT2020 to use with Calman? Can I use Hdfury for add hdr metadata anda radiance mini as pattern generator?
You don't need special patterns for the single color patterns used with Calibration software, any pattern generator will work, eg a Radiance, or MobileForge. 50% is 50% whether it's rec.709 or ST.2084, 100% red is 100% red whether it's Rec.2020 or BT.709, the difference is in how the calibration software interprets the result. And you don't need metadata injection either, the JVC doesn't use any of it anyway, just put it in the right picture mode.

However for setting bbo and clipping/etc using Arve's tool, you need to be running a properly mastered HDR pattern. This requires multi-color, multi-level patterns and those do need to be mastered for the correct EOTF/Colorspace you're trying to set up.
 

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Discussion Starter · #1,880 · (Edited)
You don't need special patterns for the single color patterns used with Calibration software, any pattern generator will work, eg a Radiance, or MobileForge. 50% is 50% whether it's rec.709 or ST.2084, 100% red is 100% red whether it's Rec.2020 or BT.709, the difference is in how the calibration software interprets the result. And you don't need metadata injection either, the JVC doesn't use any of it anyway, just put it in the right picture mode.

However for setting bbo and clipping/etc using Arve's tool, you need to be running a properly mastered HDR pattern. This requires multi-color, multi-level patterns and those do need to be mastered for the correct EOTF/Colorspace you're trying to set up.
Not really, 100% red in rec-709 isn't the same red as 100% red in BT2020. However, you are correct that UHD or HDR patterns are not needed.

What's needed is a source (it can be 1080p, that doesn't make any difference) able to generate the patterns in the correct colorspace, and to set the software so that it uses the correct colorspace/gamma curve too. For example in Calman you need to select BT2020 HDR gamut and ST2084 gamma.

You don't need to inject HDR metadata as long as you select manually the correct colorspace (BT2020) and the correct gamma curve (D or a custom gamma) in the projector.

A radiance Mini 3D should work if it supports BT2020 patterns (I never calibrated to BT2020 when I had mine so I don't know if that's supported). I use MadVR/MadTPG in 1080p and that seems to work fine too.
 
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