1. ChrisR

    ChrisR

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    I'd really like to take you up on that, John. It would let me use Peak for processing, rather than Harman. It looks like Peak are quicker (and we know their quality is excellent), but their 4x5 scan prices are daft. Harman will do process and scan for a mere £6 per frame (1200 ppi), but apparently have a week-long turnaround.
     
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  2. thedarkshed

    thedarkshed

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    Sure thing...let me know when you get the negs back ( or have developed yourself ;) ) and we can sort a date.
     
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  3. ChrisR

    ChrisR

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    I got the negatives back from Peak today. Good news and bad news. I do have images... but also AFAICS a massive light leak on both. Won't know quite what until the negatives are properly scanned, but it looks like there's a definite hard line a mm or two inside the edge of the exposed frame, and towards the middle the leak bows outwards in a half moon shape with no definite edge. I'm hoping I can pop up to @thedarkshed fairly soon for a scan and some advice. The similar position and shape of the two light leaks is rather bugging me; it seems unlikely to be from loading/unloading the DDS, as I wouldn't expect such similar (though not identical) shapes on two separate frames. Likewise, I can't quite imagine how it would happen in camera.

    I have now got my 50 sheets of Fomapan 100 (plus another DDS loaded with HP5), so I can try some more experiments...
     
  4. stevelmx5

    stevelmx5

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    Hi Chris. Sorry to hear about the light leaks. After some of the early cameras had light leaks caused by slight variances in thickness in the acrylic used on the removable backs, I've since been fitting additional external seals as standard and doing more thorough leak checks before the cameras are shipped out. Which side is the leak showing closest too?

    Cheers
     
  5. ChrisR

    ChrisR

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    This was from just sticking the negative on the home all-in-one printer-scanner...

    2018-10-24-0004.jpg

    That is the correct orientation when viewing the actual castle, so I think the light leak must be on the left hand side.
     
  6. stevelmx5

    stevelmx5

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    Looking at the sharp line I’d guess it’s either the holder where the dark slide is pulled or somewhere when the back is rotated.
     
  7. stevelmx5

    stevelmx5

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    Another option, which I’ve experienced myself, is that that film already had the light leak on it before you loaded it. I was donated a box of Fomapan when I first started working on the early Chroma design and had leaks on the developed sheets that I couldn’t figure out. It was only when I compared the sheets and found their leaks were exactly the same (when the camera had been moved around between shots) that I realised the film was already partly fogged.
     
  8. ChrisR

    ChrisR

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    I did rotate the back to landscape before taking these shots, and it's quite possible that it wasn't fitting properly. In retrospect, I also thought it was possible the dark slide wasn't in properly.

    This was from the donated set of FP4, so this is a possibility. The other loaded dark slide has HP5 in it, that came from an unopened (donated) pack. I've also just received a box of Fomapan. So if I take a few more shots I can try out the various possibilities here.
     
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  9. StephenM

    StephenM I know a Blithering Idiot

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    Can you test for light tightness simply by taking of the lens panel and shining a powerful light around the back of the camera while looking inside for leaks?
     
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  10. ChrisR

    ChrisR

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    Worth a try! Thanks
     
  11. stevelmx5

    stevelmx5

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    Definitely test using a bulb, I tend to use the led torch on my phone from a few mm away all around to check.
     
  12. FruitFlakes

    FruitFlakes

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    Check if the felt light traps are in good shape as well, I pull out the dark slide and look through the slot. Managed to mess up two sheets of 8x10 HP5 that way, checked the holder and the felt had completely worn away. The pattern of overexposure/normal exposure further in along the side reminds me a lot of what happened to mine.
     
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  13. RaglanSurf

    RaglanSurf Forum Idiot'13/14 FPOTY'17

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    Is there a way of testing film holders for light leaks other than sacrificing sheets of film?
     
  14. stevelmx5

    stevelmx5

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    You could go into a dark room and shine a torch around the edge (preferably on a mobile phone because it's a small point of light) with the dark slide remove and see if any light is visible inside the holder.
     
  15. ChrisR

    ChrisR

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    I checked this with the DDS that I used, no sign of any light through the slots at all.

    I've loaded two more DDS with Fomapan. If possible I'll shoot a couple more frames this weekend, paying particular attention to how the DDS fits. For the shots I'm thinking of, the back will probably have to be rotated back to portrait.
     
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  16. ChrisR

    ChrisR

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    My cunning plan of shooting some more last weekend came to naught (daughter suggested we venture down to Westonbirt instead). But I did take John @thedarkshed up on his kind offer of a cuppa, some scanning and a chat, very enjoyable. We had a good look for light leaks, and the good news is the bellows is sound and no obvious leaks in the camera.

    John's theory was that the hard edge to the light leak must be because the light was coming in between the DDS and the camera, with the hard line being a shadow cast by the edge of the DDS opening. I had inserted the DDS from the left hand side (RHS in the image). Fiddling around a bit, it soon became clear that the most likely explanation is that I moved the DDS slightly away from the camera body when removing or inserting the dark slide. We compared the Chroma with John's MPP, and latter has much stiffer springs holding the back in place. The good news is that it's an easy fix if you remember (and are disciplined): just hold the DDS against the camera body with fingers and thumb of one hand while removing the dark slide with the other. John realised that is what he'd been doing. Of course, if you insert/remove the dark slide under your dark cloth, that would also reduce any chance of leaks. I'm going with the jacket or T-shirt solution for now, so that might not work for me.

    Steve, if your investigations confirm this, would stronger springs be a solution? Or some kind of lock to hold the DDS against the camera back?
     
  17. stevelmx5

    stevelmx5

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    Hi Chris. I’ve just got you message on Twitter too. The possible upgrade in spring strength is something I’ve considered myself too. The 0.9mm steel used could be slightly thicker without hindering the operation so is something I’ll look into with any future modifications.

    Sorry it’s caused the leaks on your first images, at least you’ve narrowed down the issue so can adjust the way you remove the dark slide in future.
     
  18. Terrywoodenpic

    Terrywoodenpic

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    It would be worth checking the tension of the springs on an international back. None that I have see needs the addition of a lock. Though all such backs have a groove near the top. That corresponds with the ridge on the dark slide, to prevent it moving when withdrawing the slide cover. It also adds additional light trapping.
     
  19. stevelmx5

    stevelmx5

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    There’s the same groove in the Chroma back to secure the DDS in place and the springs provide tension to the ground glass to press the DDS down.
     
  20. Asha

    Asha Blithering Idiot

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    As it is becoming apparant that the cause of the light leak is possibly user error, is there any real need to make amendments to the spring strength in future models.?

    I don't have a Chroma so can't say wether I consider any improvements necessary, but I can't say I've seen any posts from other purchasers on here that have experienced problems ( unless they have and contacted you directly Steve)

    Imo if it aint broke then don't (try) fix it;)
     
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  21. Andysnap

    Andysnap POTY (Film) 2015

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    First proper test of the Chroma and I decided to make sure it wasn't too easy. A 7.5 minute exposure on OOD film.
    Home devved so there are a few water spots but it all seems to work very well.

    [​IMG]Candle and Book 1 small by Andy, on Flickr
     
  22. stevelmx5

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    Sorry Asha. I was out when I saw your post so liked it without replying. As I'm sure you know, I never really stop 'tinkering' with any cameras I build, and Chroma is no exception! I've got a few ideas on the table for future versions, mainly those I just couldn't include in the Kickstarter version due to budget/time, so all feedback from people using my cameras is very gratefully received. I've had one other backer raise a question about the springs too, mainly because he's using a Grafmatic underneath them so pushing them hard! Whilst the 0.9mm steel is a balance between weight, cost and simplicity, a thicker material would offer a stronger spring but would risk movement on the camera back when inserting the holders so it's definitely a balancing act!

    Cheers
     
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  23. stevelmx5

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    That's awesome Andy, I like testing the limits and the result looks great! Do you mind if I share your image across some of my social media pages?
     
  24. Andysnap

    Andysnap POTY (Film) 2015

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    Share away matey, no problems.
     
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  25. stevelmx5

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    Thanks bud. I'll link back to your Flickr page.
     
  26. ChrisR

    ChrisR

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    Edited: decided I didn't like the tone of this post so I've deleted it.

    Just to report that I'm still having difficulty with light leaks associated with operating the DDS in my Chroma. Not sure what the issue is, needs further investigation!
     
    Last edited: Nov 6, 2018
  27. stevelmx5

    stevelmx5

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    We'll get it sorted Chris. If Andy can nail it, anyone can ;0)
     
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  28. stevelmx5

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    Early days but I've just received my test prints for the double dry plate/sheet film holder. Long term plan is that these will be injection moulded but I wanted to check the fit/handling with a physical unit and I'm pretty happy with them. Couple of slight updates needed but nothing major.
     
  29. stevelmx5

    stevelmx5

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    IMG_1884.JPG

    IMG_1888.JPG

    IMG_1889.JPG

    The indents on the side are a combination of two standard Graflok compatible slots and three cores which are required for the injection moulding to reduce the thickness of the part as much as possible.

    At the moment this is only dry assembled around the central acrylic plate. There are also no spring seals on the top part yet.
     
    Last edited: Nov 9, 2018
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  30. stevelmx5

    stevelmx5

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    I think I've probably asked this before, but I'm interested in the collective thoughts around rear movements. Specifically, would you say that rear rise/fall is beneficial, and more so than rear shift/swing/tilt?

    I'm looking ahead to future designs (doodling really!) and am considering integrating shift/swing onto the rear standard but have seen that a number of the more 'established' cameras don't have rear rise/fall. Whilst it simplifies the build of the camera quite a lot, is it something that is worth it to have? I could include all 4 movements onto the rear standard using an updated design if it's something that would be worth the trade off against complexity/weight.

    Cheers
    Steve
     
  31. StephenM

    StephenM I know a Blithering Idiot

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    Rear rise and fall are only going to do the same as front rise and fall, although if you used both together you'd increase the amount. Rear tilt and swing will change the geometry of the image, and can be used to that end, or in maximising depth of field (I'm not attempting to correctly spell Scheimflug so I'm avoiding the word :D). Shift can be useful.

    If you have a copy of Steve SImmons book, take a look at the illustrations of the use of movements.
     
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  32. stevelmx5

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    Thanks for the quick response Stephen. My original reasoning for rear rise/fall was to work in tandem with front rise/fall and allow for a smaller range on each, to add up to a greater range together. Personally, I've always used front movements more due to the geometry being retained but, like you say, it's a useful option to have when going for more extreme movements or corrections.
     
  33. stevelmx5

    stevelmx5

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    As well as building a couple of very unique Chroma specials (photos to follow once the new owners have them), I've been spending more time on the new Chroma/Pictoriographica double dry plate holder design and am pretty much ready to print another one for final testing before looking to mould. I exported these renders last night but just need to add the upper lip on the top of the holder like a standard sheet film holder;

    [​IMG]Chroma & Pictoriographica Double Dry Plate Holder by Steve Lloyd, on Flickr

    [​IMG]Chroma & Pictoriographica Double Dry Plate Holder by Steve Lloyd, on Flickr

    [​IMG]Chroma & Pictoriographica Double Dry Plate Holder by Steve Lloyd, on Flickr

    The double holder will also come with a pair of slot in pressure plates so you also use them for sheet film so they become a dual purpose holder. They will work with both spring backs and Graflok backs to give more options too.
     
  34. Andysnap

    Andysnap POTY (Film) 2015

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    OK, excuse my thickidity (real word!!!) but what is a dry plate, where do I get one and why do I need one? :D
     
  35. stevelmx5

    stevelmx5

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    A dry plate is like a wet plate that's dry ;0)

    https://www.pictoriographica.com/

    Basically, whereas wet plate photography means that you have to coat the glass plate on site with collodion (under a safe light), sensitize it in a silver bath, load it in a holder, shoot it then develop it (under a safe light) before it dry's out, dry plates are pre-coated and can be loaded in a dark bag like a sheet of film, shot, then developed afterwards. The resulting plates are excellent quality (ASA 2) and give a similar unique result to wet plate.
     
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  36. StephenM

    StephenM I know a Blithering Idiot

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    Dry plates offer two big advantages over cut film. Or perhaps two and a half.

    1. They are dimensionally stable, and won't shrink or expand.

    2. They are a lot heavier, and by carrying a number around for your photography you can not only save the costs of gym membership, but avoid the need to spend time there. Just taking photographs is enough for a good work out.

    2 1/2. Being coated on glass, they are breakable, and this introduces a whole new realm of possibilities for ruining your exposures.

    and, as an afterthought, with Christmas coming up.... Process to produce a positive transparency, then drop it and give it as a jigsaw puzzle.

    Go on, you know it makes sense.

    Edited for the inevitable typo.
     
  37. Asha

    Asha Blithering Idiot

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    2 boxes of 5x4 dry plates ordered…..Expected delivery, monday next week …..



    .................via a HHAULAGE company! :LOL:
     
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  38. Andysnap

    Andysnap POTY (Film) 2015

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    Mmm, £32.54 for 10 plates, colour me interested. :)
     
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  39. Asha

    Asha Blithering Idiot

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    Perhaps them plain white Greek one are cheaper!:D
     
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  40. stevelmx5

    stevelmx5

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    If you can read German, Jason has just started selling his plates through this German company;

    http://schwarzweiss-fotolabor.de

    Cheers
    Steve
     
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