Comparison of E6 Labs in UK for Astia/Velvia

<p>I've recently been making a c<a href="http://www.timparkin.co.uk/blog/velvia_astia_provia_pro160_digital">omparison of different film types</a> and the issue of variance of the labs themselves was raised in relation to some of the strange colour I was getting with Astia.<br>

In order to find out what possible differences their may be, I tried sending the same picture taken on Astia and Velvia to three different labs in the UK - The Darkroom, NPS Media and Peak Imaging. <a href="http://www.timparkin.co.uk/blog/saltwick">The results I got were quite interesting..</a> <br>

I would be interested in your interpretation of these and any suggestions for further tests. <br>

Tim<br>

p.s. The subject matter was an overcast evening in the Lake District and the scans have been done on an Epson v750 with Silverfast on completely manual settings. The results were then checked visually against a calibrated screen. I plan to do another test with some more challenging colours - to begin with I wanted to check greens and overcast skies as they seem to show the greatest problems... <br>

p.p.s I've been told that I should try using a 2C UV filter when out in sunny conditions and looking at the colour curves for Velvia, they do go wierd below 400nm</p>

<p>For any meaningful comparison you need to repeat this test every week for maybe at least one month and possibly longer, to see any variance in each labs processing on a weekly basis. One test proves nothing, other than that different batches of film, chemicals, processing temperatures and times will alter colour...but we know that already without any test.</p>

<p>You would have to make sure all film is the same batch, stored in the same way. All shot on same day at same time, and enough films to send to three labs for at least four successive weeks. You really should shoot under studio conditions to ensure consistent light conditions. Use a colour test chart.</p>

<p>Even if you did a much better test, who knows that the week after you test, another batch of film has different colour, OR the lab you decide is 'best' then changes its chemicals and the colour changes again.</p>

<p>This is precisely why IMO all comparitive testing like this is one big waste of time.</p>

<p>I was a studio pro shooter in the 80's. We shot Fuji 5x4 large format trannies in the studio and used our own E6 line. The line was very closely monitored. We still had colour changes with EVERY different batch of film and every change of chemicals. We had to shoot test trannies with each batch of film and each batch of new chemicals....do you want to do that? are you capable of running your own E6 line? If either answer is no, then stop wasting your time....only my opinion.</p>

<p>cheers Steve.M.</p>

<p>I don't if they have them in the UK, but you may want to look for a certified Kodak Q-Lab. They have to send samples of processed films to Kodak twice a week to make sure the quality is the best possible.</p>

<p>Sorry Steve but your opinion does seem questionable. Obviously this can never be a definitive "Look that lab is shite!" but it is not 'wasting my time' unless it gives zero useful information. I'm pretty sure it gives 'some' useful information.<br>

If I have a bunch of developer labs and I get results back where one looks reasonable colour and the other two look out. I can make better educated opinion of which lab will produce better results. Of course I may be wrong, but I am more informed than I was if I had just chosen randomly. If send another test to those three labs and the results support my first results then I am even better informed than I was before..<br>

Obviously you disagree with my understanding of probability..<br>

Tim<br>

p.s. Your answer contained some a small amount of useful information but without knowing what sort of colour casts you are talking about, it doesn't amount to much (are you talking tiny mired values? did you get contrast changes? Was it the amount of colour cast that you might get from an 80 or 81 A?). You don't mention whether you got the same colour shifts when you sent your E6 off to professional labs and you don't mention whether or what value of colour shift you got if you developed the same exposure taken on different batches of film with the same chemicals.. Overall most of what you say, without further information, could be written off as a badly calibrated E6 run.<br>

I do have colleagues who run their own E6 line and have no problems with colour shifts between A and B sheets run through different chemicals. What E6 line did you run and did you ever do and A/B comparison with commercial labs?</p>

<p>p.p.s. If you are stating as an absolute that E6 can never be developed with consistent colour, could you help inform the film using population of what scale of mired shift, contrast change or colour cast is within typical bounds? This would help me greatly in assessing my own E6 line.. (for instance, looking at my comparisons, would you say this was a typical variation in film colour for different chemical developing assuming the same film batch)</p>

<p>If I were going to undertake such a test, I'd attempt to expose numerous chromes at nearly the same instant. If you're using sheet film you can do this with a single camera. But if you're using roll film, I'd suggest loading three or four cameras with the same type of film, hopefully manufactured in the same batch, purchased on the same day, and stored in the same way.</p>

<p>Snap off one exposure on each camera in as short a time frame as possible. Light can change in seconds, especially under the dynamic skies of the British Isles. Repeat the one-shot-per-camera process for each successive image. When you have enough test shots, drop one roll off at each of your test labs. It's probably better to deliver them in person so that you can control the film's temperature at all times. The postman might let one of your packages bake in a hot van for a day or two negating the fairness of the test.</p>