. Elementary and dental radiography / by Howard Riley Raper . no longer sensitive to light), the shadow of the bones of the handwill appear as transparencies; the flesh shows a little less transparentthan the bone, and the balance of the plate will be opaque and the shadows show light, and where no shadow was thrown the plateis dark. Hence the name negative which is applied to this picture onthe plate. The making of the positive picture on paper, the print, as it MAKING RADIOGRAPHS 79 is usually called, from the negative will be described presently. Theplate is no longer sensitive t
. Elementary and dental radiography / by Howard Riley Raper . no longer sensitive to light), the shadow of the bones of the handwill appear as transparencies; the flesh shows a little less transparentthan the bone, and the balance of the plate will be opaque and the shadows show light, and where no shadow was thrown the plateis dark. Hence the name negative which is applied to this picture onthe plate. The making of the positive picture on paper, the print, as it MAKING RADIOGRAPHS 79 is usually called, from the negative will be described presently. Theplate is no longer sensitive to white light, and may therefore be exposedto it any time after having been in the fixer a minute or so. Great care must be exercised not to get any of the fixing bath intothe developer. A very little hypo will spoil the developer. It is wellto label the trays so that the tray used to hold the fixer one time will notbe used for the developer another. Or, instead of labeling the trays, ablack one may be used for the developer and a white tray for the Fig. 74. Fixing box. Fig. 75. Plate, or negative, rack. When fixing is completed the negative must beUlashing. washed in clear water to remove all hypo from it. If the negative be placed in a tray, the tray in abasin or sink and the tap turned on. or, in other word:, if the negativebe washed in running water it requires 15 to 30 minutes to thoroughlywash it. Where running water cannot be had,* and sometimes duringhot weather when tap water is too warm, the negative may be placed ina larger vessel of water and left for about an hour, changing water sev-eral times. A tray of water used on a titubator is efficient. The watermust be changed often, and the time required is about three-quarters ofan hour or longer. When several negatives are being made, it is ad-visable to use a washing box similar to the fixing box. (Fig. 74.) * Running water is much to be preferred, as the friction or movement ofthe water is a great factor in cl
Size: 2216px × 1127px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., book, bookauthorraperhowardriley, bookcentury1900, bookdecade1910
