1. _A reticulated appearance on the film after developing._--When this is universal, it often depends upon the employment of Collodion containing water. Or, if not due to this cause, the plate may have been immersed too quickly in the Bath, and the soluble Pyroxyline partially precipitated. 2. _Oily spots or lines._--_a._ From raising the plate out of the Nitrate Bath before it has been immersed sufficiently long to have become thoroughly wetted.--_b._ Removal of the plate from the Bath before the Ether upon the surface has been washed away.--_c._ Redipping the plate in the Nitrate Bath after exposure to light, and pouring on the developer _immediately_; if a few minutes be not allowed to drain off the excess of Nitrate, the Pyrogallic Acid will not amalgamate readily with the surface of the film.--_d._ From the Nitrate Bath being covered with an oily scum, which is carried down by the plate. Draw a slip of blotting-paper gently along the surface of the liquid before using it. 3. _Straight lines traversing the film horizontally._--From a check having been made in immersing the plate in the Bath. 4. _Curved lines of over-development._--By employing the developer too concentrated; or by not pouring it on sufficiently quickly to cover the surface before the action begins; or by using too little Acetic Acid, and omitting the Alcohol. The addition of Alcohol to the developer will not be required as a rule when the Bath is newly made; but when much Ether has accumulated in it, the developer has a tendency to run into oily lines, unless containing Alcohol. 5. _Stains from too small a quantity of fluid having been employed to develope the image._--In this case, the whole plate not being thoroughly covered during the development, the action does not always proceed with regularity. 6. _Irregular striæ._--From fragments of dried Collodion accumulating in the neck of the bottle, and being washed on the film; to avoid this, the finger should be passed gently round the inside of the neck before use. 7. _Markings like those represented in the woodcut._--They are caused by using an inferior sample of Pyroxyline made from too hot acids, and are most seen when using an old Bath. [Illustration] 8. _Stains on the upper part of the plate, from using a dirty slide._--To avoid these, place, if necessary, strips of blotting-paper between the supports and the glass. 9. _Wavy marks at the lower parts of the plate._--_a._ If the Collodion is becoming thick and glutinous from constant use, dilute it with a little Ether containing an eighth part of Alcohol.--_b._ From reversing the direction of the plate after its removal from the Bath, so that the Nitrate of Silver flows back again over the surface and causes a stain on the application of Pyrogallic Acid.--_c._ Impurities on the woodwork of the frame ascending the film by capillary attraction. This is a frequent source of stains.