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Ektachrome 64 Filtering question....


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#1 Alessandro Machi

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Posted 28 May 2005 - 11:07 AM

If I use an 85B filter with Ektachrome 64, will bringing the warmer tones out increase grain noise as the blue grains "battle" the orange grains?

Asked another way, which will look less grainy, Ektachrome 64 properly exposed with an 85 filter, or Ektachrome 64 properly exposed with an 85B filter?
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#2 David Mullen ASC

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Posted 28 May 2005 - 12:31 PM

If I use an 85B filter with Ektachrome 64, will bringing the warmer tones out increase grain noise as the blue grains "battle" the orange grains?

Asked another way, which will look less grainy,  Ektachrome 64 properly exposed with an 85 filter, or Ektachrome 64 properly exposed with an 85B filter?

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The 85B and 85 are so close that it just depends on the color balance you want, but it is within a realm that any post adjustments one way or the other isn't going to affect grain. You're just talking about the difference between 3200K and 3400K. There is a bigger range in color temp than 200 degrees throughout the daytime.

For example, the 85B correction may be better in overcast weather if you are worried about too much coolness. In the late afternoon, you may like the 85 filter to remove some warmth. But again, this is within an easy range of correction in post without any adverse affects. It's not like shooting without either filter and correcting 5500K to 3200K in post.

However, if this is for direct viewing, you may want to use the correct filter if you can't adjust color in post.

In terms of simply using the color filter in general, there would be no affect on graininess (assuming you expose correctly) until you attempt to make a correction, so the bigger the correction, the more grain you may get in the underexposed color layer.

Because daylight shifts in color, plus you may want a cooler or warmer tone for artistic effect, using the 85B instead of the 85, or vice-versa, doesn't automatically mean you'd want to make an adjustment in post anyway.
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#3 Alessandro Machi

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Posted 28 May 2005 - 09:57 PM

In terms of simply using the color filter in general, there would be no affect on graininess (assuming you expose correctly) until you attempt to make a correction, so the bigger the correction, the more grain you may get in the underexposed color layer.

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That is the prime issue for me. If I'm in a rank transfer facility and I want to make an "adjustment" to the Ektachrome 64, my concern is I will see more grain if I try to flush out a full color scale range from blue and green to orange, red and yellow.
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#4 David Mullen ASC

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Posted 29 May 2005 - 01:56 AM

That is the prime issue for me.  If I'm in a rank transfer facility and I want to make an "adjustment" to the Ektachrome 64, my concern is I will see more grain if I try to flush out a full color scale range from blue and green to orange, red and yellow.

<{POST_SNAPBACK}>


But the adjustment is incredibly minor if you are talking about the difference between an 85 and an 85B. There would be no affect on grain. In fact, the difference is so small that depending on scene content, you may make no adjustment at all, or a bigger adjustment that had nothing to do with the filter -- like I said, daylight varies much more in color temp throughout the day, so even if you shot with the correct 85 filter, you'd probably STILL be making corrections more extreme the difference between an 85 and an 85B just to match a shot at noon to a shot made at 4 PM, or a shot made in the shade to a shot made in sunlight. Even HMI lights vary more in color temp between them than the difference between an 85 and 85B.

If your Rank causes noise or grain to appear when you make a tiny 200 degree Kelvin adjustment in color, there's something seriously wrong with the machine... that's like an 18 MIRED shift, like a 1/8 CTO gel difference.

If you're this worried about it, why not just use an 85B filter on the front of the camera instead of the internal filter?
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#5 Alessandro Machi

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Posted 29 May 2005 - 06:45 AM

I am planning on using an 85B on the front of the camera. I'm interested in the "trend" the Ektachrome film will show as it is warmed up, rather than measuring how little the change really is.

If with a regular 85 filter one sees "X" amount of grain, but with an 85B filter, one can see slightly more grain because of the blue versus orange grains in the film, then it will be more difficult to emulate Kodachrome 40 by warming up the film.
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#6 Sam Wells

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Posted 29 May 2005 - 09:22 AM

Read David's post carefully - there is no grain issue here. You wouldn't see increased grain if there was a 200 degree shift in color temperature in daylight.

85 vs 85B is maybe 1 printer point's difference.

Or, if you saw that little difference between how 2 different Cintel machines were set up, I'd be surprised !

-Sam
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#7 Alessandro Machi

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Posted 29 May 2005 - 11:46 AM

Or we could all focus on the key word "trend". What is the characteristic of the Ektachrome film as it is warmed up.
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#8 David Mullen ASC

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Posted 29 May 2005 - 12:01 PM

Or we could all focus on the key word "trend".  What is the characteristic of the Ektachrome film as it is warmed up.

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Warmed up how much? If you use the in-camera 85 filter in daylight, it is being cooled down by a miniscule amount, and if you use the 85B filter, it would be normal, not warm.

As you go further than that, obviously a warmer image is warmer. There shouldn't be an effect on grain unless you attempted to correct it out, and the more warmth you apply, the bigger the correction to remove, the bigger the effect on grain in some layers, etc.

But we're talking about more dramatic shifts in color than the difference between an 85 and 85B filter so I don't really get what you want to hear except for what we've already told you. I think we've been pretty clear that you shouldn't have a problem adjusting for the DIFFERENCE between an 85 and 85B filter.

Minor adjustments in color do not affect the overall graininess. Bigger adjustments in color may affect grain or noise in certain colors but not overall. Huge adjustments in color really mean significant underexposure of some color layers.

Did Kodachrome get grainy when lit by 3200K pro movie lamps instead of 3400K photofloods as it was designed for? I never saw any sign of that. That's a 200 degree difference. Does an image get grainy when shot at sunset?

And we're talking about when shooting a gray scale. In the real world, for artistic reasons, one often shifts the color slightly warm or cool. Like I said, once you time an outdoor scene EVEN IF YOU USED THE CORRECT FILTER, you often make adjustments to the color because daylight is rarely at photographic daylight, i.e. 5500K.

If you want to test the changes in grain from using a lot of warmth in the image and correcting it out, you'd have to start with a more dramatic jump than 200 degrees Kelvin to begin to see anything.

If you want to prove that Super-8 is a professionally valid stock, then it better be able to handle a single printer point of color adjustment without becoming visibly MORE grainy because it would be a useless format otherwise. Because you make bigger adjustments in that just matching actors fleshtones sometimes, let alone variations in natural light. Super-8 is not THAT bad at handling a range of colors and you should know that by now.

There is only one reason why you should use EXACTLY the correct filter to balance color reversal, and that is when you have NO ability to make color-corrections, as with direct projection of the original. And even then, if you simply thought that using the correct 5500K-to-3200K filter was enough, you wouldn't necessarily get perfectly balanced colors because the real world is not perfect. If you do have color-correction capability, an 85 and 85B are so close as to be almost interchangeable, a small enough difference to easily adjust for in post.

You've never made a post color-correction of more than an 18 MIRED shift in all your films? Never slightly warmed up or cooled down a shot? I'm not sure why this is new to you.
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#9 Anthony Schilling

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Posted 29 May 2005 - 05:11 PM

I guess the 200 degree difference is insignifigant enough for Kodak to recommend the 85 filter with ECN films instead of an 85B. ECN tungston films are 3200K as well, but according to an online discussion I read (David was in on) Kodak decided on a coin toss to go with an 85 filter based on the yellow curves of ECN films and familiarity I guess? Ekta reversals respond a little different so they recommend an 85B. An 85B will also cut at least 1/3rd stop than an 85?
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#10 Alessandro Machi

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Posted 29 May 2005 - 05:29 PM

I think what is being missed here is I am trying to ascertain what would produce the closest look to Kodachrome 40 by using Ektachrome 64. Would matching the less grain look require keeping the image slightly cool? Will warming up the Ektachrome film ever so slightly begin to cause more different colors of grain to become noticeable?

I sat in on a Rank session and when the super-8 film was warmed up, I could see more grain then when the film was kept slightly cool. The film was old and outdated, but I did notice that when the film was warmed up, it did look grainier.

In my opinion, emulating a Kodachrome look with Ektachrome64 will require warming filters, how much I do not know. Perhaps slightly more than an 85B filter will be required. I am curious if one trys to emulate Kodachrome 40 with Ektachrome 64 by using a warming filter, if that will make the Ektachrome 64 look more grainy than if one keeps the Ektachrome 64 slightly cool.

Ergo, can Ektachrome 64 be made to look like Kodachrome 40? If adding additional warming filters to the Ektachrome 64 increases grain, then the answer would be no, if adding additional warming filters does not increase grain, then it might be possible to make the Ektachrome 64 look similar to Kodachrome 40.
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#11 David Mullen ASC

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Posted 29 May 2005 - 05:44 PM

I guess the 200 degree difference is insignifigant enough for Kodak to recommend the 85 filter with ECN films instead of an 85B. ECN tungston films are 3200K as well, but according to an online discussion I read (David was in on) Kodak decided on a coin toss to go with an 85 filter based on the yellow curves of ECN films and familiarity I guess? Ekta reversals respond a little different so they recommend an 85B. An 85B will also cut at least 1/3rd stop than an 85?

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The 85 is really the 85A filter, made for Type A films, 3400K (the 85B filter is made for Type B films, 3200K).

Well, most people don't realize that an 85B doesn't cut 2/3 of a stop -- it cuts a little more than that. Most charts will probably tell you that an 85 filter cuts a 1/2 stop while an 85B filter cuts 2/3 of a stop because they are rounding up or down. It's more like an 85 filter cuts almost 2/3 of a stop and an 85B filter cuts maybe 7/8 of stop.

The 85 filter transmits 70% while an 85B filter transmits 60%. An ND.30 filter transmits 50%. I don't know if that calculates as a 1/3 stop difference between the 85 and 85B (my math isn't so good...)

Part of the problem is just that the term "85" can mean either the 85A or 85B filter. So when someone says "I pulled the 85 filter" they can mean either.
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#12 David Mullen ASC

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Posted 29 May 2005 - 06:16 PM

There's no reason why a slight warming in post would make an image grainier, and there is no reason at all why a slight warming filter on the camera would alter the grain in the image. And we're talking slight if we are talking about the difference between an 85 and 85B.

What, are you going to eliminate all warm scenes in a movie? No sunset shots? How can one avoid warmth if filming the real world?

>I am curious if one trys to emulate Kodachrome 40 with Ektachrome 64 by using a warming filter

Why would a warmer image emulate Kodachrome? Kodachrome can be cool, warm, or neutral depending on how you shoot it or what you are shooting. It's not inherently warmer-looking than Ektachrome (some colors may saturate differently though -- K40 may have stronger reds, for example.)

Now Kodak did make some "warm-biased" daylight Ektachrome still camera stocks but these were deliberately color-balanced for people who wanted a slight warmth outdoors without resorting to warming filters.

I think you are overthinking this issue. E64T is balanced for 3200K. It needs an 85B filter when shot under 5500K lighting. K40 is balanced for 3400K. It needs an 85 filter when shot under 5500K lighting. In both scenarios, with proper filter correction, the image on both is neutral.

If E64T is shot under 5500K with an 85 filter, the image is slightly cooler. If K40 is shot under 5500K with an 85B filter, the image is slightly warmer.

However, since HMI lighting and true daylight both vary from 5500K, these factors also affect warmth and coolness too, so using the "correct" filter does not guarantee a "correct" color-balance. Which is why some people carry 81EF's, 812, etc. for further adjustment of warmth in-camera, or they save it for post.

Like I said, if Super-8 films cannot handle a minor color-adjustment in post equivalent of a 1/8 CTO gel on a light, without becoming visibly more grainy, it's pretty useless for filmmaking. But I know that's not the case.

It seems to me that you're looking for a non-existent problem to blame on Kodak.

K40 and E64T are not identical stocks. They will never match each other EXACTLY. Kodachrome has a unique look. It has nothing to do with grain, sharpness, and saturation -- modern E6 stocks can be pretty similar. It has to do with the DYES used in Kodachrome, which are unique because they don't use color-coupler technology. They feel and look different in DIRECT PROJECTION.

However, transferred to a digital format or copied for printing, that uniqueness is muted if not lost because it is TRANSPOSED into another format's color process. If your concern is simply grain, sharpness, and saturation, modern E6 stocks rival Kodachrome in those purely technical areas -- that's not what makes Kodachrome unique. It's more subtle than that. It's more like the difference between a dye transfer print and an Eastmancolor print.

Not having shot E64T, I can't say that is the the E6 stock that matches K40 the closest either in terms of color and contrast. Most of the tungsten-balanced color slide film Kodak makes is more neutral in color reproduction, with a more natural contrast -- not as snappy as some of the daylight stocks like E100HC (I don't know if they still call it "HC" anymore...) E64T is probably the closest match in terms of speed and color balance, but in terms of the "Kodachrome look", one of their 100 ASA stocks may be a better match. However, differences in color saturation and contrast can be adjusted for if transferring the film to video.

If you want to see this as a crisis, that's up to you, but this issue of E64T being balanced for 3200K and K40 being balanced for 3200K is a non-problem. As for warming up or cooling down an image in post, in small degrees, there should be no affect on grain with either stock. In major degrees, there can be grain and/or noise problems. In terms of on-camera filtration, simply filtering an image with a color cast shouldn't inherently change the graininess unless it is an extreme color (like a very blue image, since the blue layer is the fastest and grainiest with a tungsten-balanced stock.)
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#13 Daniel Henriquez Ilic

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Posted 29 May 2005 - 08:04 PM

Alessandro,

The film was old and outdated, but I did notice that when the film was warmed up, it did look grainier.


But if the film was out-dated... it is not really an objective reference.

May be it would be a good idea that you test the EPY stock in 135 format. You can then scan it or transfer it to video.

Regards,
Daniel

Edited by Daniel Henriquez Ilic, 29 May 2005 - 08:09 PM.

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#14 Scot McPhie

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Posted 29 May 2005 - 08:49 PM

  I am trying to ascertain what would produce the closest look to Kodachrome 40 by using Ektachrome 64. 


You could probably start by killing all that horrible unecessary exposure lattitude ;-)

Scot
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#15 Alessandro Machi

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Posted 29 May 2005 - 08:52 PM

David, there is a reason that Ektachrome comes in a blue box and Kodachrome 40 comes in an orange box with a red stripe, and the reason isn't strictly for marketing purposes.
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#16 Alessandro Machi

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Posted 29 May 2005 - 09:12 PM

Alessandro,
But if the film was out-dated... it is not really an objective reference.

Regards,
Daniel

<{POST_SNAPBACK}>


I agree Daniel, I simply brought that up because the film could look "cool" and look fine, but when the color was made more true to life, it became more grainy. The film was so outdated I don't even know for sure that it was Ektachrome.

May be it would be a good idea that you test the EPY stock in 135 format. You can then scan it or transfer it to video.

Regards,
Daniel

<{POST_SNAPBACK}>


I'm of the opinion that unless one sees frame to frame real time motion, the amount of grain is harder to determine.
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#17 Alessandro Machi

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Posted 29 May 2005 - 09:21 PM

You could probably start by killing all that horrible unecessary exposure lattitude ;-)

Scot

<{POST_SNAPBACK}>



hahahaha, good one.

But is it possible the extra latitude is "blue based"?

I'm not assuming anything, but I sure am anxious to test this Ektachrome 64 out and see how the warmer tones flesh out.
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#18 David Mullen ASC

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Posted 29 May 2005 - 11:21 PM

I'm of the opinion that unless one sees frame to frame real time motion, the amount of grain is harder to determine.

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Actually moving images REDUCE visible grain because your eye/brain sort of samples and blends the grain of the adjoining frames, so a still frame is the worst-case scenario for graininess (i.e. the easiest way to see it). You can figure that it will look better when moving, and even better at higher frame rates than slower frame rates. If you are COMPARING the graininess of two stocks, using still frames is a perfectly accurate way of judging the DIFFERENCE.

The color of a box of film has nothing to do with its color reproduction...
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#19 Alessandro Machi

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Posted 29 May 2005 - 11:35 PM

The color of a box of film has nothing to do with its color reproduction...

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I couldn't disagree more, when it comes to Super-8 Ektachrome and Kodachrome.
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#20 David Mullen ASC

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Posted 30 May 2005 - 12:01 AM

I couldn't disagree more, when it comes to Super-8 Ektachrome and Kodachrome.

<{POST_SNAPBACK}>


Do you honestly think Kodak used a blue box for Ektachrome because it creates a bluer image? I suppose any Kodak stock with a green stripe is designed for stronger greens. And they ALL handle yellows really good, of course -- the color of the box tells you that. Even their b&w films are great with yellows...

Whether or not Kodachrome has richer reds, the color of the box is irrelevant. It may be as simple as Kodachrome, being first invented, got a red-striped box and Ektachrome, invented later, just got a blue stripe on the box to make it look different on the shelf than the red-striped Kodachrome. They could have just as easily picked a purple stripe, but blue is considered the opposite of red, so it seemed a good idea to have two opposite colors for the boxes of their two color reversal products.
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