Ektar 100 now in 120 format

[Ed_Ingold]

<p><em>it’s fairly safe to add 1 to 1.5 stops to that in real world use.</em></p>

<p>Interesting. What is your basis for this statement?</p>

<p><em>Of course, I normally make real world tests rather than analyzing a chart. </em></p>

<p>I take it you have a step wedge and densitometer. I know of no way to do this otherwise. We're talking about limits of the medium, not composition or beauty, and how would you know, objectively, the dynamic range of a scene. Given your propensity for "fudging" the results (see the first quote), your "real world" results would be whatever you wanted them to be :-)</p>

<p>I disagree with your choice to measure that far down the toe of the curve. IMO, there's no contrast there, hence it is of no photographic significance. Did you bother to measure the slope at that point? At least you stated your assumptions in a way anyone could reproduce - that's a step in the right direction.</p>

<p>Fun aside, there is nothing to be gained by publishing exaggerated and unsubstantiated data, whether financial or scientific. The film does what you want or it doesn't. You like the results or you don't. It compares well or poorly against competing media. My priorities may differ from yours. The specifications merely help us understand (and potentially use) the natural limits of the medium.</p>

[Dave Luttmann]

<p>A case in point of this is the charts for Tri-X indicate a range of approx 12.8 stops, yet when I did step wedge tests a number of years back with a 2 bath method of processing, I obtained a decent 14 stops....which is more than the chart suggests. I have always found that analyzing the charts is kind of a waste of time. If the charts told you 10 stops for the film, and everyone only ever got 7, then there's no point in quoting the charts, is there?</p>

<p>Regards,</p>

[Ed_Ingold]

<p><em>If the charts told you 10 stops for the film, and everyone only ever got 7, then there's no point in quoting the charts, is there?</em></p>

<p>Assuming the manufacturer wasn't fudging the data - a poor move for a technical company - I'd want to know why I wasn't able to get there myself. Actually, 7 stops is a pretty wide range for useful detail in any scene. How would anyone actually know they were only getting 7 useful stops?</p>

<p>The processing chemistry and method is part of the specifications behind the chart. This is fairly fixed for C-41 film. However it is possible to push or pull the speed, which affects the contrast, dynamic range and, unfortunately, the color balance.</p>

<p>It is much simpler and more reliable to do this with Tri-X (or silver-based B&W in general). It is an integral part of the Zone System as expounded by Ansel Adams and others. At one point in time, Kodak published several processing scenarios along with characteristic curves, for Tri-X. Perhaps they still do.</p>

[Dave Luttmann]

<p>Edward, I add that 1 to 1.5 stops to what I get from a chart based upon testing. Different processing methods effect the range as well. That is why using one chart as the reference point is hardly accurate. As to measuring that far down the toe, the same can be said for digital tests where once the 9th, 10th or 11th stop of quoted range is measured, the bit depth is leaving 4 or 8 tonal values to work with.....hardly useful either.</p>

<p>The tests I did a number of years ago where done with a step wedge and a freshly calibrated Macbeth TD 1224 transmission/reflection densitometer.</p>

<p>Kodak does still post different charts....but not many. Still better than one I guess.</p>

[q.g._de_bakker]

<p>Why don't we now just wait until it is available, and then run it through our cameras?</p>

[mauro_franic]

<p>Log2(10^1.2 / 10^-2.2) = 12.6 stops<br>

The problem is that we are using a chart of tiny size that was meant to show the density/exposure charateristics to accurately determine the number of stops it can capture.<br>

for example<br>

if you look at the publication of TMX 100 you would come up with similar values 12.6 stops, given the tiny chart.<br>

___________________<br>

It is easier and truer to run your own test. Run a roll of Ektar you can develop at Costco for $1.5 and shoot something doubling the shutter speed every time. Shoot your DSLR alongside. Compare.</p>

 

[Ed_Ingold]

<p>Log2(10^1.2 / 10^-2.2) = 12.6 stops ??</p>

<p>No, you still don't get the math. Read my post again - I developed the entire proof in meticulous detail. At least you something written for a reference. When I taught (chemistry), I would write with one hand and erase with the other, or just say "It can be shown..." ;-) The proof would be your homework assignment.</p>

[djcphoto]

<p>Well, ignoring the pissing contest above, I for one am looking forward to just shooting the stuff! Thanks Kodak!</p>

[mauro_franic]

<p>What power do I need to rasie 2 at, in order to get bright to dark ratio of 10^1.2/10^-2.2...</p>

[Ed_Ingold]

<p>Actually, I get a dynamic range of 9.3 stops for TMax 100 developed in D76 for 7.5 minutes at 68 deg F. Slow, fine-grained film usually has more contrast and a smaller dynamic range than the old standby - Tri-X.</p>

[Dave Luttmann]

<p>Waste of time pursuing this further. It's agreed the film is better than the digital. It's a film thread. Let's all go and expose a few rolls of this and quit bickering.</p>

[Ed_Ingold]

<p><em>What power do I need to rasie 2 at, in order to get bright to dark ratio of 10^1.2/10^-2.2...</em></p>

<p>x = (1.2 + 2.2)/0.301 = 11.2946</p>

<p>To check the results (there is a roundoff error in x, if anyone cares about 1/10,000 of an f/stop)...<br />2^11.2946 = 2512<br />10^1.2/10^(-2.2) = 15.849/0.00631 = 2511</p>

<p><em>Dave said, "...It's a film thread..."</em></p>

<p>This is a technical question with regard to film. Would you care to participate or just sit on the sidelines and complain?</p>

[Ed_Ingold]

<p>Sorry. Here is the T-Max 100 chart, JPEG this time...</p>

[Ed_Ingold]

<p>I will try one more time, then get back to work...</p><div></div>

[max cooper]

<p>Wow. Lots of interesting scientific stuff in this thread. <br>

I just did a test of Ektar 100. Not as precise as all this, but I'm happy with it. I found that the box speed is pretty dead-on, and compared the grain favorably to Portra 160NC and Delta 100.<br>

Here's a link:<br>

<a href="http://darktopography.blogspot.com/2009/02/ektar-100-darktopo-film-test.html">http://darktopography.blogspot.com/2009/02/ektar-100-darktopo-film-test.html</a></p>

[silverscape]

<p>I doubt that many people are going to read through all <strong>118</strong> posts in this topic now.<br /><br />But here is something that should clear everything up...all you have to do is look at the posting history for people who wander into film topics to bash film. That explains it all. They're all digital. They never post in any of the film forums at all. It's a pattern that I see every single freaking time. You look at someone who says they're not "bashing film" but they keep repeating the same, old, tired crap about "film is going extinct" "film is dead"...blah blah blah. Oh, they may not come out and say that exactly. But they'll make neat little analogies...like comparing Kodak to a mammoth. Then you look at their posting history, and you see that ALL of their topics are in the <em>digital </em>forums. They NEVER post in any of the film forums. They could care less about film. They only post comments in film topics to make an anti-film remark. So no surprise there. <br /><br />In fact, in the past two years or so that I have been on Photo.net, I have already seen the same pattern happen over and over again. What always happens is that as soon as a film topic shows up in the "active threads" on the Photo.net front page, inevitably someone will wander in from the digital forums to start making remarks. It happens every single time. Someone will post an optomistic news article about film, and everyone will get excited...and then like clockwork, a troll wanders in from the digital forums and decides that it's their job to 'set everyone straight' and 'remind' people that "oh, film is dead" "Kodak doesn't make any money from film" blah blah blah.<br /><br />How about this...how about the film users go to the digital forums and 'remind' them that the large majority of the average digital camera users are emo kids taking lame "kewl pics" (usually of themselves, in front of a bathroom mirror with the flash on and the camera tilted) for their MySpace page? That the average digital user is people getting their blurry, pixelated snapshots printed at Walmart, and they have absolutely no real interest whatsoever in photography? Guess what....THOSE are the people who are mostly buying digital cameras. Should we do that?<br /><br />No, of course not. But to me, it seems just as fair. How about this...if you don't use film, <strong>then don't post in a film topic</strong>. I'm not interested in digital cameras (I have one, but I only use it for quick snapshots)...so I don't post in the digital forums. I have never seen a film user wander into the digital forums and start bragging about the pictures he or she took with Ektar 100 or Plus-X. So tell me...WHY do digital users feel the need to <em>constantly</em> wander into the film forums to say "film is going extinct" and nonsense like that? If you don't like film, if you don't use film...then don't go into the film forums. Stick with what you enjoy. And I'm also completely fed up with seeing people wander into the Film and Processing forum, just to make smart remarks.<br /><br />If you don't use film...then don't go into the film forums. How hard is that??<br /><br />ANYWAY...<br /><br />There is a good discussion about Ektar 100 right now, in the Film and Processing forum...you know, for people who actually LIKE film and actually <strong>USE</strong> film.</p>

[steve m smith]

<blockquote>

<p>They could care less about film.</p>

</blockquote>

<p>For non American readers, he means 'couldn't care less about film'.</p>

<p>Not being picky (yes I am) but it just sounds odd.</p>

<p>Anyway, I agree with everything you said in the post above.</p>

[lilserenity]

<p>I think the thing that bugs me most is not the film + digital thing (I couldn't care a less, I use film -- but use whatever you want, it's a free country) - but it's the thread crapping.<br>

This <em>was</em> a thread about Ektar 100 now being available soon in 120 format.<br>

Now it's a thread about dynamic range, the EOS 40D DSLR versus other films and some graphs which I personally have never encountered and am not interested in personally, especially what was a discussion about the nice news that a very good C41 film will be released in 120 format.<br>

Would I be out of order to suggest that the conversation about graphs and maths and stuff like that was moved into a new thread which is devoted to that discussion.<br>

Or do the interesting threads have to all be crapped on eventually with some other discussion to suit the most dominant voice that shouts the loudest?</p>

[Dave Luttmann]

<blockquote>

<p><a href="../photodb/user?user_id=419409">Edward Ingold</a> <a href="../member-status-icons"><img title="Subscriber" src="http://static.photo.net/v3graphics/member-status-icons/sub8.gif" alt="" title="Subscriber" /> <img title="Frequent poster" src="http://static.photo.net/v3graphics/member-status-icons/3rolls.gif" alt="" title="Frequent poster" /> </a> , Feb 19, 2009; 10:58 p.m.</p>

<p><em>Dave said, "...It's a film thread..."</em></p>

<p>This is a technical question with regard to film. Would you care to participate or just sit on the sidelines and complain?</p>

</blockquote>

<p>Considering I started this thread, and considering your post has NOTHING to do with what I posted as the OP, maybe you could sit on the sidelines or stay on topic. Thanks.</p>

<p>And Chris, I agree with you 100%. The one thing yo didn't mention is the how they do it. They post in a film thread, and while not always directly bashing film, they try to do it in a subtle way. Then when you protest in the least.....they act all innocent and make out like you're attacking them because of some fault of our own.</p>

<p>I don't mind the dynamic range test stuff as it interests me. The funny thing is that some of these people have posted elsewhere that digital beats film DR....now they just argue over the math, whule agreeing that some films win out. It's been interesting watching some of the opinions change over the years as these people have educated themselves or tried film.</p>

[photo_smith]

<blockquote>

<p>Edward Ingold<br /> Since the toe of the curve becomes nearly horizontal (zero contrast, hence zero detail), it is necessary to assume some arbitrary starting point. I created lines with a 10% and 50% slope and found the point where they just touched the curve (the tangent point). That is, a given change in exposure would change the density by 10% and 50% respectively, which is proportional to a contrast ratio. 10% contrast is very low, and image features would be barely discernible*. At 50% and low level, the contrast is closer to what you would consider "shadow detail".</p>

</blockquote>

<p>><br>

Why use ANSI standard curves and estimate a starting point? You do realise there is a formula laid down in the ANSI standard for the calculation of that point?<br /> Picking your own 'arbitrary' start point means that you are just guessing the latitude of the film, you can't find absolutes from estimates.<br /> Dave L used a figure from lower down the curve which you didn't like 'because it contains no photographic detail' <br /> His start point is no less valid (and actually a better guess when you use the correct formula) than yours as they are both guesses.<br /> In pictorial photography you would generally put the shadows on the toe of the curve, and the highlights on the shoulder as the eye can't detect the non linear values in those parts of the image.<br /> This leaves the linear part to represent the mid tones where the eye is more sensitive to change in tone, it is a mistake to only count the linear part, in fact many well known experts place zone 0 on the far left so the first detail containing tone step normally (1-2) falls on the up-tick of the curve.</p>

[Dave Luttmann]

<p>Very true Mark. That is why when I simply do the math from a chart, I add 1 to 1.5 stops to what I can achieve in real life as using the chart is simply a latitude guess as you stated. But in the end, it doesn't really matter though. Ektar was designed to be a higher contrast, saturated film. DR and latitude were not really as much a consideration. Of course, Ektar still appears to beat out what most DSLRs can obtain.</p>

[Ed_Ingold]

<p>Mark said...<br /><em>you can't find absolutes from estimates ... it is a mistake to only count the linear part, in fact many well known experts place zone 0 on the far left so the first detail containing tone step normally (1-2) falls on the up-tick of the curve.</em></p>

<p>I use the term "estimate" in the scientific sense. In measurement science there are no absolute data, just estimates. There is always uncertainty in a measurement. Sometimes there are also assumptions. Since I stated the methods and values I used, the analysis can be repeated by anyone, even with different assumptions.</p>

<p>You will notice that I did not choose an arbitrary starting point, rather a minimum contrast, which is proportional to slope of the curve. The "linear" or mid-part of the curve is not a consideration. If there is an ANSI standard with respect to the minimum contrast value, I would be easy to start from that point. Please provide some details if you have that standard in hand (ANSI publications are only available on a subscription basis, and are very expensive).</p>

<p>In order to determine the tangent point, I drew a line (in Adobe Illustrator) with a specified slope (Transform/rotate/arbitrary), then moved it until it just touched the curve. You can bump an object one pixel at a time with the arrow keys. The line is sharp and the curve is fuzzy, but it's not hard to get a good match. The uncertainty in the X direction is probably less than 0.1 units. The slope setting is in degrees, which is equal to the arctan of the slope in units of the graph.</p>

<p>Dave states (again) that he adds 1 to 1.5 stops to the measured range. Now that is truly arbitrary, and hardly qualifies as an assumption in the scientific sense ;-) It is not hard to understand why unnamed "experts" would measure from the extreme left end of the curve. It is a quasi-scientific way to exaggerate the dynamic range. I'm not sure that's what happens. By convention, there is no detail visible in Zone 0, so it is rightfully placed one step to the left of the last visible border between steps, which is probably about the 10% contrast point, not the end of the curve. When shooting a step wedge, there are usually several steps to the left of Zone 0.</p>

<p>An acquaintance who regularly posts on PNET (and is truly an expert) said it would be a waste of time to explain how characteristic curves work. In once sense he was right, because it's easier to repeat mantras than to search for the truth. However photography is as much craft as art, and much of that craft is based on science.</p>

<p>ommmm...ommmm</p>

[danielleetaylor]

<p>Edward - I appreciate your posts, work, and explanations. Much of it I've seen before in various sources and to the best of my knowledge you have presented an accurate explanation of curves, and an accurate evaluation of Ektar's published dynamic range. At this point the people disagreeing with you are not disagreeing based on any finding of fact, but on baseless personal opinions quite likely shaped by bias. Human nature...</p>

<p><em>it's easier to repeat mantras than to search for the truth</em></p>

<p>Yep.</p>

<p> </p>

[Dave Luttmann]

<blockquote>

<p>Dave states (again) that he adds 1 to 1.5 stops to the measured range. Now that is truly arbitrary, and hardly qualifies as an assumption in the scientific sense ;-) It is not hard to understand why unnamed "experts" would measure from the extreme left end of the curve. It is a quasi-scientific way to exaggerate the dynamic range. I'm not sure that's what happens. By convention, there is no detail visible in Zone 0, so it is rightfully placed one step to the left of the last visible border between steps, which is probably about the 10% contrast point, not the end of the curve. When shooting a step wedge, there are usually several steps to the left of Zone 0.</p>

 

</blockquote>

<p>You know Ed, I really wish people in forums would learn to read. It is not arbitrary....it is based upon how I read the chart, do the math, and then compare that to what I achieve in the real world with a Densitometer test.</p>

<p>Just to be clear yet again....I add that 1 to 1.5 stops to the figure I get from charts because that is what I achieved in testing with the films. I don't think I can be more clear that it is not arbitrary. You can parade terms like "unknown experts" all you like.....I would much rather be an unknown expert obtaining accurate results than the links we've seen posted by people to sites that have been proven incorrect so many times that I have to wonder at the intelligence of those who continue to quote them.</p>

<p>The question I have for you is other than guessing at where to begin your measurement from a chart....have you ever done any deenity tests yourself that refute the figures that a number of us have obtained....and some have even posted? I have to wonder as the information you keep posting is quite contrary to those of us who scan film regularly and have tested many films over the years.</p>

[Dave Luttmann]

<blockquote>

<p ><a href="http://www.photo.net/photodb/user?user_id=2129602">Daniel Lee Taylor</a> <a href="http://www.photo.net/member-status-icons"><img title="Frequent poster" src="http://static.photo.net/v3graphics/member-status-icons/1roll.gif" alt="" /></a>, Feb 20, 2009; 11:05 a.m.<br>

Edward - I appreciate your posts, work, and explanations. Much of it I've seen before in various sources and to the best of my knowledge you have presented an accurate explanation of curves, and an accurate evaluation of Ektar's published dynamic range. At this point the people disagreeing with you are not disagreeing based on any finding of fact, but on baseless personal opinions quite likely shaped by bias. Human nature...</p>

 

</blockquote>

<p>Coming from someone who doesn't even own a step wedge nor densitometer....and hasn't done any testing.....those of us who have find the above to be completely laughable.</p>