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  1. #1

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    Feb 2003
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    Well I guess by now you are all getting tired of this fellow asking all of those questions and he does not even have the stuff yet.

    Well I finally stepped off and began the process.

    I ordered my Richeson brush (actually two of these) today.

    So... after a bit more thought I will be continuing on or else learning how to paint.

    Hope to be attending Les McLean's workshop this weekend in Calgary. Maybe he knows about Pt/Pd processes.

    Kind Regards,
    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

  2. #2

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    James,

    If you don't know the best way to use these, here it is:

    The brush is used totally wet (saturated with water). Dip it in distilled H2O and get it completely soaked. When you pull it out, you'll discover that the brush makes a really nice razor edge tip. That's what you are paying the money for.

    Take the brush and shake it off pretty agressively onto the floor. I shake it at least once in the four orientations of the brush (flat, two sides, and on edge, two sides).

    The brush should now still be quite wet but not dripping, and the bristles should form a solid edge with no gaps or seperations. If you get seperations, you need a little more water. I don't think you can shake too much water out in a few shakes, but if you do, redip, and start over.

    Now you are ready to coat. Pour the solution on the paper, dip the brush in the center, and then start spreading reasonably fast. You want to get the solution evenly coated as fast as possible, because otherwise you may have problems with blotchiness in the print.

    When you're done, rinse it well and dip it in some distilled water as a final rinse. Leave it sitting wet for your next coating session.

    ---Michael

  3. #3

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    Thanks Michael. I am going to need to know how to do that.

    Well step number two now taken. I ordered a Pt/Pd kit from Bostick & Sullivan yesterday. (a Christmas present from my wife) I spoke with Kevin and as some of you folks have already stated, he indeed enjoys explaining these things on the phone. Had a real good conversation with him that I quite enjoyed.

    Hopefully over the Christmas holidays I can do my first 4x5 contact print. Now the last piece of the puzzle is to figure out how to go about building a UV light source. The building part is not a problem for me but selecting and purchasing the lights might prove to be an educational journey.

    Kind Regards,
    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

  4. #4

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    James,

    There is a very useful link for this here:

    http://www.eepjon.com/ubldit.htm

    They have basically complete directions for building a UV light unit. I recommend you also check out the links they have, as they list sources for the lamps you will want to get.

    They recommend the correct lamps in the article, which are known as blacklight lamps (or BL in the lamp code). There are others that will work, including blacklight-blue (BLB), which are the traditional lamps used for lighting blacklight posters, etc. These are not as efficient, and will probably cost more, so I don't recommend them.

    Make sure you build the light big enough to accommodate the largest size print you reasonably expect to print in the future. You don't want to have to do it again if you get an 11x14 camera. I strongly recommend you give yourself at least 6" of lamps beyond the end of the print in all directions. If you don't you will have uniformity problems at the edges.

    If there are Grainger stores in Canada, you will be able to get everything you need from them, including lamps, ballasts, sockets, switches, etc. You'll have to order online, as none of the stores will carry the lamps.

    There is a bit of misinformation out there about the speed of the printer. With the FL tube bank, the speed is primarily dictated byt the lamp type, and then the lamp spacing. It is best to have them spaced the absolute minimum you need to get the lamps installed, and not have any gaps between them, other than a fraction of an inch. As long as you build the bank large enough, the distance between the lamps and the print will not affect the printing time much, within reason.


    ---Michael

  5. #5

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    [quote="Michael Mutmansky"]James,


    "They have basically complete directions for building a UV light unit. I recommend you also check out the links they have, as they list sources for the lamps you will want to get."

    Also, have a look at my article on UV light sources at http://unblinkingeye.com/Articles/Light/light.html


    "They recommend the correct lamps in the article, which are known as blacklight lamps (or BL in the lamp code). There are others that will work, including blacklight-blue (BLB), which are the traditional lamps used for lighting blacklight posters, etc. These are not as efficient, and will probably cost more, so I don't recommend them."

    I have done a lot of testing of different types of UV fluorescent tubes, including BL, BLB, SA (Super Actinic) and AQUA. The differences in usable UV radiation for Pt/Pd between them are really too insignificant to be much of a factor. The BLB tubes that Michaels cites as not as efficient as BLs print in Pt/Pd only about 1/8 of a slower than BLs, and about 1/4 stop faster than the NuArc. I have bank of (12) 48" BLB tubes. I bought the BLB tubes instead of BLs because they were available at a very good price at a home supply store (Lowes) locally. Many distributors will not ship 48" tubes. The BLs in that size would have cost more than twice as much per tube and I would have had to order them so for small loss in efficiency the advantage in convenience and cost made me favor the BLBs in my own situation.

    For what it is worth I rank the efficiency of various sources for pt/pd printing as follows, 1. BL, 2. SA, 3. BLB, 4) NuArc. But all things considered they all give virtually identical results with a real difference in printing speed of no more than 1/4 of a stop, so buy according to price or convenience and don't get hung up on the idea that you must have one specific tube.

    When I did the article on UV lights a couple of years ago I really expected to see greater difference in performance based on anecdotal information, but careful testing proved otherwise.

    "Make sure you build the light big enough to accommodate the largest size print you reasonably expect to print in the future. You don't want to have to do it again if you get an 11x14 camera."

    Good idea if you have the space because it costs only a tad more to build a unit with 36" or 48" tubes than with 18" or 24" tubes.


    "There is a bit of misinformation out there about the speed of the printer. With the FL tube bank, the speed is primarily dictated by the lamp type, and then the lamp spacing."

    I don't agree with Michael on this one. The major difference I have found is not in the lamps but in the ballast, which can result in more than a one stop difference in printing speed. Electronic ballast is both more efficient and consistent than iron or magnetic ballast, and ballast designed for HO (high output) and VHO (very high output) is the most efficient of all, even with tubes of normal output.

    "As long as you build the bank large enough, the distance between the lamps and the print will not affect the printing time much, within reason."

    Very true. There is virtually no difference in printing speed with the frame at 3" from the lights and at 6" from the lights.

  6. #6

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    Sandy,

    Of course, using an HO or VHO ballast will be a faster printing method, but at the substantial expense of the lamp life. Using these ballasts with normal output lamps is not recommended, and may not be electrically safe due to the much higher amperage that the lamps are operating at.

    If you look at the ends of the lamps, you will probably see what's known as end-wall blackening. This is a result of the cathodes in the lamps sputtering off the tungsten that makes up the cathodes. This will occur much more rapidly with an improperly driven lamp, and will eventually cause the lamp failure.

    Additionally, the extra heat that is generated by overdriving the lamps will bake the phosphers, and reduce the efficiency of the lamp more rapidly, so you had better have a very good way to remove the heat generated by the lamps.

    Personally, if you want to use a HO or VHO ballast, be my guest, but it's not something I would do. Besides, if you are concerned about cost, then using an HO or VHO ballast is definately not going to be on your solution sheet, as they tend to be very expensive compared to normal output ballasts.

    If you get normal output ballasts, it may be possible to find three or four lamp electronic ballasts, which will reduce the number you have to buy. If you use HO or VHO, you probably won't find electronic ballasts, so you will need one ballast for every two lamps. Combine this with the higher cost per ballast, and you suddenly get a much more expensive setup, that is much less energy efficient, and will burn up the lamps more quickly.

    I do recommend electronic ballasts, even though they cost more. Make sure you get the appropriate ballast for the lamp. Some of the BL lamps are T-12 lamps, and most electronic ballasts are for T-8, so be sure that you are getting the appropriate ones. Also, make sure that all the ballasts are of the exact same manufacture. This is important because the actual output from ballasts can vary by manufacturer, and you can get differences of as much as 10-15% in lamp output depending on the operating characteristics of the ballast. That can cause uneveness on the image under certain circumstances.

    BLB lamps are essentially BL lamps with an added Wood's filter applied to the glass before the phosphers are coated onto the glass. There is no possible way that they will ever be as efficient as a BL lamp, although the difference may be slight. If they are readily available at a reasonable cost, then I suppose it may be a reasonably alternative, but you have to be more careful around these lights.

    The BLB lamps don't have the majority of the visible spectrum that the BL lamps contain. This will result in a relatively 'dark' appearence to the light, which is useful if you have a bunch of phychedelic posters or whatever, but this also means that your pupils will be dialated with this light source, which can result in your eyes receiving much more UV light than with the BL (or other) lamps.

    While this isn't an issue if you do this a few minutes a week, if you spend a lot of time around the lamps, you might want to be more careful about eye protection. Most home centers have good safety glasses that will eliminate a very high percentage of UV. They should be used if you are going to be around any of these light sources a lot, but it is much more important around the BLB lamps.

    In most cases, the 2' BL or BLB lamps have about 10,000 hour life expectancy, and the 4' lamps have about 20,000 hour life expectancy, and the 4' lamps are often priced cheaper than the 2' equivalents, due to volume issues. I would recommend making a 4' unit. It will allow you to print on multiple negatives at any one time, or on larger neagtives without difficulty, and there is almost no drawback to the larger lamps, other than the larger unit, which reduces portability, and the increased energy usage when in operation.


    ---Michael

  7. #7

    Join Date
    Sep 2003
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    North Vancouver, Canada
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    7
    Tom Ferguson has a tutorial on his web site for building a UV lightbank.

    http://www.pipeline.com/~tomf2468/altinstruct12.html

  8. #8

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    [quote="Michael Mutmansky"]Sandy,

    "Of course, using an HO or VHO ballast will be a faster printing method, but at the substantial expense of the lamp life. Using these ballasts with normal output lamps is not recommended, and may not be electrically safe due to the much higher amperage that the lamps are operating at."

    I am not advocating using normal output tubes in VHO ballast because the cost would be prohibitive. And you may well be right about the shorter life. But this combination does work and will put out more light, at least visually, than normal tubes in regular electronic ballast. Whether more useful UV light is radiated is another matter. In fact, in tests I have done there was virtually no difference in printing speed between a unit with VHO ballast and 75 watt VHO tubes and regular 20 watt output tubes in electronic ballast. The VHO unit put out a lot more visual light but it did not translate to increased printing speed. I don't know how to explain this but it is something I have tested and comfirmed several times.

    "BLB lamps are essentially BL lamps with an added Wood's filter applied to the glass before the phosphers are coated onto the glass. There is no possible way that they will ever be as efficient as a BL lamp, although the difference may be slight."

    The filter makes virtualy no difference in actual printing speed. There is a difference, but it is is almost miniscule (about 1/6 or 1/8 of a stop). But the difference does favor the BLs slightly. However, there is one advantage to using the BLB lights and that is the fact that the light highlights any little bits of dust and crud that might fall on your printing glass. The look is really quite amazing and really helps in reducing dust spots on the print.

    "The BLB lamps don't have the majority of the visible spectrum that the BL lamps contain. This will result in a relatively 'dark' appearence to the light, which is useful if you have a bunch of phychedelic posters or whatever, but this also means that your pupils will be dialated with this light source, which can result in your eyes receiving much more UV light than with the BL (or other) lamps."

    To say that the BLB are more of a danger than the BLs is confusing. Because of the filter they actually put out the same or slightly less UV light than the BLs, and in any event most of us print in rooms with the room lights on where our eyes would already be dilated and shield the light of the UV printer from our eyes (and if don'te we should).

    However, if you go to a wild party where there are a lot of BLB lights strung up get some UV goggles immediately.

  9. #9

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    Sandy,

    What you have to consider about BLB lamps is that they do not APPEAR very bright to our visual system.

    In both lamps, the UV exposure is similar, but in the case of the BLB, the UV component is a MUCH HIGHER PERCENTAGE of the output of the lamp.

    When you look at the BLB lamp, your pupils don't automatically constrict in the regular self-preservation manner, because the human visual system does not account for UV when it determines what a safe size the pupils should be.

    So, you could be working under fairly subdued light in the coating area, with fairly large pupils, and then go into the exposure room under low light, place the negative and paper, and mess around near the exposure unit for a while.

    All the while, your pupils can be fairly dilated due to the relatively low amounts of visible light. However, the UV in the room is off the chart, and your eyes are getting a healthy dose that could be much greater than what they would get outside, because the pupils have not constricted due to the disparity between UV and visible percentages in the room.

    There can be a big difference in the pupil size of a room that has a low ambient light level that is generally considered suitable for pt/pd to avoid fog, and those of a person using the Sun for exposure, for example.

    The light levels that most people work under are quite low, probably in the 10 to 20 footcandle range, and it wouldn't surprise me if there are many that are below 10 fc in the coating area. More important, the use of low wattage incandescent, and other low color temperature light sources (that have little or no UV component to avoid fog) will exacerbate the problem of pupil dilation because the human visual system is keyed more toward the blue end of the spectrum. So under the same light level and exitance conditions, the pupil will be more dilated when the light source is yellow-white, than it will when the light source is blue-white.

    As I said, this is not an issue for an occasional user, but it is an issue if you print a lot, because the damage caused by UV is cumulative.

    The exposure can be a real problem if you spend time looking directly into the light source to check for dust or or other problems as you mention, because of the extreme amounts of UV radiation that is present under the exposure area.

    Basically, don't be massing around near the UV exposure unit without eye protection, regardless of the lamp source, and there won't be any long term issues. Of course you know this, but most people don't think about this type of thing too much, and it has to be said for the sake of education.

    ---Michael

  10. #10

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    Michael,

    You must work in very different conditions from me. I work in a room with a lot of light and my UV printer is always shielded so when it is on there is virtually no light leaking out. The only time I work in low levels of light is when coating and drying sensitized mateial, and in those circumstances I sure am not going to have the UV light on!!

    But one can not be to careful in protecting their eyes from UV light.

    In any event this has strayed from the point. You stated that you did not recommend BLB tubes. What I wanted to do was point out that these tubes are in fact highly efficient in printing alternative processes. They are just slightly slower than BL tubes, print virtually on par in tems of speed with AQUA and SA tubes, and are quite a bit faster than NuArc 26-1K. Plus, as I mentioned in the earlier message, the strange light really highlights debris that tends to settle on the glass of the priinting frame or vacuum easel, which really helps to make clean prints.

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