Re: [pinhole-discussion] Ground glass and baking soda in Dektol
On Sat, 27 Apr 2002, Jim Noel wrote: > As for BAking soda in dektol, don't do it. The use of baking soda will > increase the activity of the developer and thus create mor cpontrast, not > less. > Jim I disagree. I have experimented with this. When I added baking soda to dektol it decreaed the contrast to some extent. I believe Dektol uses Sodium Carbonate as its alkali agent - it has a pH of around 11 in solution Baking Soda is made of sodium Bicarbonate - it has a pH of around 8 in solution. Adding Baking Soda should lower the pH to some extent. I don't know if the sodium carbonate and sodium bicarbonate react in any way at room temperature. In my experiments it has. There are better ways of reducing contrast, so I don't really recommend using this in practice, but I was curious to see if it would work. Gord - Gordon J. Holtslander Dept. of Biology hol...@duke.usask.ca112 Science Place http://duke.usask.ca/~holtsgUniversity of Saskatchewan Tel (306) 966-4433 Saskatoon, Saskatchewan Fax (306) 966-4461 Canada S7N 5E2 -
Re: [pinhole-discussion] Re: [pinhole-discussion]ground glass
on 10/6/41 7:10 pm, Richard M. Koolish at kool...@bbn.com wrote: >> >> Thankyou all for the input on ground glass >> >> Guillermo- >> >> The reason for the ground glass is so that I can view the scene for >> composition before exposure. I don't require a necessarily good image, just >> one for the main lines and masses of the picture. Your idea of a fresnel >> sheet is inspired, I shall use it. I know that pinhole is also about >> serendipity but I want a little more control over the final image, >> particularly when one has taken time to find and there is no retake! >> >> I am going to use a viewing pinhole for the ground glass - one that gives me >> enough light (under a cloth) so I can see the image. I am not concerned >> with viewing detail just the main masses. >> >> Alexis > > > Why not make a viewfinder instead Two reasons - I want to see exactly what the camera will see without parallax error, particularly for closeup work; to avoid uneccessary croping and make maximum use of the film surface I am practicing to make a lens large format camera Alexis
Re: [pinhole-discussion] Re: [pinhole-discussion]ground glass
> > Thankyou all for the input on ground glass > > Guillermo- > > The reason for the ground glass is so that I can view the scene for > composition before exposure. I don't require a necessarily good image, just > one for the main lines and masses of the picture. Your idea of a fresnel > sheet is inspired, I shall use it. I know that pinhole is also about > serendipity but I want a little more control over the final image, > particularly when one has taken time to find and there is no retake! > > I am going to use a viewing pinhole for the ground glass - one that gives me > enough light (under a cloth) so I can see the image. I am not concerned > with viewing detail just the main masses. > > Alexis Why not make a viewfinder instead?
Re: [pinhole-discussion] Re: [pinhole-discussion]ground glass orientation
Thankyou all for the input on ground glass Guillermo- The reason for the ground glass is so that I can view the scene for composition before exposure. I don't require a necessarily good image, just one for the main lines and masses of the picture. Your idea of a fresnel sheet is inspired, I shall use it. I know that pinhole is also about serendipity but I want a little more control over the final image, particularly when one has taken time to find and there is no retake! I am going to use a viewing pinhole for the ground glass - one that gives me enough light (under a cloth) so I can see the image. I am not concerned with viewing detail just the main masses. Alexis
Re: [pinhole-discussion] ground glass orientation
You may wish to try the BTZS focus cloth - http://www.darkroom-innovations.com/BTZS_Focus_Cloth/btzs_focus_cloth.html. I don't use one, but I've heard positive comments. Cheers - george --- Jeff Dilcher wrote: > > I have a Finney camera, and the ground glass is completely useless to me. > Supposedly, the larger pinhole on the rotating turret is supposed to be > large enough to view an image on the ground glass, but I don't find this > is the case. Maybe if I tightly wrapped a focusing hood so that not a > single bit of light leaks through, I might see something! The designer of > the camera even agreed with me, and admitted that the camera was > originally intended as a lens camera- hence the addition of the ground > glass. That having been said, it is nice to be able to swap out the > pinhole turret for a lens/lensboard, and quickly convert to a lens camera, > if I wish... > > If you created "guide lines" on the top and side of your camera, you will > be able to compose our photo much more quickly and easily than ground > glass. Ground glass, imo, is really only necessary for focusing, and > there is no need to focus with pinhole. > > But, to answer your question, I believe the "smooth" side of the ground > glass is on the outside of the camera... > > > ___ > Post to the list as PLAIN TEXT only - no HTML > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??? > unsubscribe or change your account at > http://www.???/discussion/ = Handmade Photographic Images http://GLSmyth.com DRiP Investing http://DRiPInvesting.org __ Do You Yahoo!? Yahoo! Games - play chess, backgammon, pool and more http://games.yahoo.com/
Re: [pinhole-discussion] Re: [pinhole-discussion]ground glass orientation
- Original Message - From: "ragowaring" To: Sent: Monday, April 22, 2002 8:17 AM Subject: [pinhole-discussion] Re: [pinhole-discussion]ground glass orientation > I am building a pinhole field camera with ground glass viewing screen. > Can anyone tell me which way round the ground glass surface faces. Does it > face front towards the pinhole (lens) or the back of the camera? Alexis, It really doesn't matter for pinhole. It only matters when using glass lenses, where the distance lens to ground side of the GG must be exactly the distance between lens to film. Nevertheless, I'd put the smooth side facing you. While you are at it, go to your nearest office supply store and buy a fresnel lens, they sell them a reading aids, cut a piece (from the center) equal to the size of your GG and mount it either in front or at the back of the GG, it will make your GG brighter. Guillermo
[pinhole-discussion] Re: [pinhole-discussion]ground glass orientation
I am building a pinhole field camera with ground glass viewing screen. Can anyone tell me which way round the ground glass surface faces. Does it face front towards the pinhole (lens) or the back of the camera? Alexis
Re: [pinhole-discussion] ground glass
Found this on the cameramakers list Try this: obtain some glass cut to size (this can be from your friendly glass shop or from picture frames - I get mine at garage sales). Go to your local auto parts emporium and get a tube of valve grinding compound. Squirt some between two pieces of glass, and with a circular motion rub the top sheet of glass over the bottom sheet of glass. Make sure you get complete coverage. If the valve grinding compound starts to dry out, clean off both plates of glass and squirt in some more compound. Rub for about 10 minutes, wash off the glass and see if it is "ground" to your satisfaction. If not, do some more. > > From: "Murray" > > > > > > > Has anyone ever tried making a 'ground glass' viewing plate (or whatever > > you > > > call it), either with 'non-glare' etched picture framing glass, or > > > subjecting a piece of this or other glass to additional abrasion? > > > > I have used aluminum oxide powder, water to form a paste, elbow grease and a > > small piece of glass to rub the paste in circular motion. You keep doing it > > until the results are even (5 to 10 minutes for 4x5 a piece of glass) . I > > use 600 grit aluminum oxide, would love to try finer grits but haven't found > > locally, besides, 600 gives satisfactory results, you can find the powder in > > science stores and in lapidary supply stores, few ounces is enough for all > > your life time needs. I believe some people have used rubbing compound used > > to polish car paint jobs, I have no experience with that product. > > > > Guillermo > > > > > > > > ___ > > Pinhole-Discussion mailing list > > Pinhole-Discussion@p at ??? > > unsubscribe or change your account at > > http://www.???/discussion/ > > > > - > Gordon J. Holtslander Dept. of Biology > hol...@duke.usask.ca 112 Science Place > http://duke.usask.ca/~holtsg University of Saskatchewan > Tel (306) 966-4433Saskatoon, Saskatchewan > Fax (306) 966-4461Canada S7N 5E2 > - > > > ___ > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??? > unsubscribe or change your account at > http://www.???/discussion/ > - Gordon J. Holtslander Dept. of Biology hol...@duke.usask.ca112 Science Place http://duke.usask.ca/~holtsgUniversity of Saskatchewan Tel (306) 966-4433 Saskatoon, Saskatchewan Fax (306) 966-4461 Canada S7N 5E2 -
Re: [pinhole-discussion] ground glass
I've used sand-paper on acrylic plastic - Don't think its nearly as bright as groundglass - but I've only used groudglass in a lens camera - haven't compared them properly. It may work for something cheap and easy. Gord On Thu, 20 Dec 2001, G.Penate wrote: > > - Original Message - > From: "Murray" > > > > Has anyone ever tried making a 'ground glass' viewing plate (or whatever > you > > call it), either with 'non-glare' etched picture framing glass, or > > subjecting a piece of this or other glass to additional abrasion? > > I have used aluminum oxide powder, water to form a paste, elbow grease and a > small piece of glass to rub the paste in circular motion. You keep doing it > until the results are even (5 to 10 minutes for 4x5 a piece of glass) . I > use 600 grit aluminum oxide, would love to try finer grits but haven't found > locally, besides, 600 gives satisfactory results, you can find the powder in > science stores and in lapidary supply stores, few ounces is enough for all > your life time needs. I believe some people have used rubbing compound used > to polish car paint jobs, I have no experience with that product. > > Guillermo > > > > ___ > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??? > unsubscribe or change your account at > http://www.???/discussion/ > - Gordon J. Holtslander Dept. of Biology hol...@duke.usask.ca112 Science Place http://duke.usask.ca/~holtsgUniversity of Saskatchewan Tel (306) 966-4433 Saskatoon, Saskatchewan Fax (306) 966-4461 Canada S7N 5E2 -
Re: [pinhole-discussion] ground glass
- Original Message - From: "Murray" > Has anyone ever tried making a 'ground glass' viewing plate (or whatever you > call it), either with 'non-glare' etched picture framing glass, or > subjecting a piece of this or other glass to additional abrasion? I have used aluminum oxide powder, water to form a paste, elbow grease and a small piece of glass to rub the paste in circular motion. You keep doing it until the results are even (5 to 10 minutes for 4x5 a piece of glass) . I use 600 grit aluminum oxide, would love to try finer grits but haven't found locally, besides, 600 gives satisfactory results, you can find the powder in science stores and in lapidary supply stores, few ounces is enough for all your life time needs. I believe some people have used rubbing compound used to polish car paint jobs, I have no experience with that product. Guillermo
