الفشل - التعرف على الأخطاء وتصحيحها .. اختيار واستخدام المواد .. كتاب التصوير الضوئي

**Ali Abbass** · 09-05-2024, 08:53 PM

Failure - Identifying and Correcting Errors ..
Selecting and Using Materials .. The Book of Photography

Selecting and Using Materials
Failure

Identifying and Correcting Errors:

It is better to avoid making mistakes than to seek to correct them later. In other words, it is preferable to retake the picture - if possible - rather than trying to save it by uncertain laboratory work. If retaking is impossible or it is impossible to replace it, first take the best possible picture before trying chemical treatment. In general, do not bother to find an explanation for the failure if it does not recur, and instead look for the cause of the failure if it does recur. Knowing that light-sensitive areas or treatment solutions are sometimes blamed, the main cause of the failure is an error on the part of the photographer himself.

Never load your machine with film in the sun. Make sure that the 35 mm film is securely attached to the receiving reel inside the machine and that the holes are fully set on the toothed roll before closing the machine case. If the film does not advance in the machine, it means that it will not be exposed. Monitoring the progress of 35mm film It is enough to look if the machine's rotating tool (manifold) rotates when feeding the film. For 35mm film, correct processing should show numbers and letters in the margins of the negative image: if this is the case and the film does not contain an image, blame the machine or the exposure. If the film is completely white, including the margins, this means that the processing is incorrect.

When purchasing the film, check its expiration date and avoid using expired film: when the expiration date of the film expires, it loses some of its speed and becomes obscured. For color films, age causes a dominant color to appear or an imbalance in the color tones. Process as soon as possible after taking the pictures. Place the raw films in a cool, dry place.

Old machines, especially machines with bellows, can have small holes in their black chamber, which then act as stenopic, meaning that they produce images, especially in light, that distort the film. You can check the sealing of the film by placing a flashlight in the box and examining the outside of the machine in complete darkness: small gaps will then be visible directly.

Airport X-ray inspections create a general veil on the films, so carry your films in your hand luggage.

The lens gets covered with steam when a cold machine enters a warm room, so let the lens lose this steam before you start taking pictures.

When you are taking pictures, look at your subject until the moment you take the picture. A common mistake is poor framing that cuts off an important part of the subject, such as the top of the head or hands, for example: this mistake is due to an inaccurate focuser, but most often to involuntary poor framing while taking the picture. With simple machines, it is always preferable to remove the glasses before framing in the focuser.

Underexposed negatives - in color and black and white - are characterized by their weak density and lack of detail in the shadows. Overexposed negatives, on the contrary, are very dense, especially in the very bright areas of the subject. The opposite is true for slides, which are very straight if underexposed and very light if overexposed. Marginal veils (thick on negatives and light on slides) are due to light passing between the cheeks of the reel or its edge. If there is a similar veil in each image, this means that this veil occurs in the machine every time you feed it. Carefully protect the exposed or photographed films. You can put them in their original box and put a sign on them indicating that this film is ready for development.

◾ Failure in negatives and slides:
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Appearance
Possible cause
Comment
---------------------------------
- Negative too dense or slide too light.
- Overexposure.
- Observe the speed value declared on the positometer or on the machine. Check the shutter speeds and pre-select the pupil (reflex).
---------------------------------
- Negative too light or slide upright.
- Underexposure.
- Check the speed value declared on the positometer or on the machine. If the weather is very cold, increase the exposure time slightly.
---------------------------------
- Signs on the negative.
- Static electricity.
- This appears if the weather is hot and very dry. Re-feed the film slowly.
---------------------------------
- Small white dots on the negative and black on the positive.
- Dust on the film during exposure.
- Clean carefully inside the machine.
---------------------------------

- Polygonal spots in the shape of a pupil are based on the negative and bright on the positive.
- Light reflections directly into the lens.
- Avoid direct sunlight in the lens.
---------------------------------
- Lines along the film.
- Abrasion in the machine.
- Make sure that the feed coils in the machine are of the type. They rotate completely freely. A grain of sand between the lips of the cartridge can cause this line.
---------------------------------

◾Failure when taking pictures:

- Appearance
- Possible cause
- Comment
---------------------------------
- Lack of clarity in the picture. One level may appear clear.
- Bad calibration.
- If this error is repeated regularly, the machine should be checked, otherwise it is a calibration error.
---------------------------------
- General vibration in the picture and sometimes the presence of clouds in high lights.
- Vibration in the machine while taking the picture.
- Press the button slowly. Use faster film if necessary. Hold the machine well.
---------------------------------
- Shaky image in part.
- Move the subject while taking the picture.
- Use a faster shutter speed or avoid taking pictures of subjects that are moving quickly.
---------------------------------
- General ripple in the image.
- Punching in the paper protecting the film.
- This only happens with old, damp roll films.
--- Overlapping image.
- Poor film advance.
- Check the film advance mechanism.
- ...

◾Color photography failure:

Color film can present the same errors as black and white film plus some of its own. The previous plates are also acceptable for color but with some differences. For example, a veil caused by light filtered from the edges of the film is yellow on reversible color film.
Color negatives are not concerned with the plate below because a general dominant color can be corrected during enlargement and excessive contrast in a color negative image is due to incorrect development.
- ... Or also incorrect processing.
---------------------------------
- Red spot in the eyes when using flash.
- Light reflected by the retina. Keep the flash lamp away from the optical axis of the lens. In 110 machines, use a long flash.
---------------------------------
- Dominant bluish color and poor contrast when using flash.
- Smoky atmosphere. Do not shoot when smokers are present in a poorly ventilated room.
---------------------------------
- Landscape where the views are far bluish.
- It is the atmospheric veil that leads to this dominant blue color: use an anti-ultraviolet filter.
---------------------------------
- Reddish colors in the image, especially in faces.
- A picture taken in the last hours of the day.
---------------------------------

◾Failure with magnification papers:

- Appearance
- Possible cause
- Comments
---------------------------------
- Obscured margins
- Light sensitive mixture veil
- Chemically ineffective, bad or ineffective paper.
- ... - Uneven image development is usually caused by an overexposed image that you are trying to save by shortening the development time.
---------------------------------

◾Failures encountered in processing:

This is specified in the table below, and it occurs when you process your films yourself, we are exposed to serious errors, as it is known that manual traces are caused by fingers soaked with chemicals.

- Scene.
- Possible cause.
- Comment.
---------------------------------
- Arc-shaped marks on the film.
- Film breakage when filling it in the tub.
- Especially in films placed in the reel. There is no treatment for it, just be careful.
---------------------------------
- Light areas along the edges of the film.
- Static electricity.
- Finger pressure along the film while filling it in the screw.
---------------------------------
- A light edge area than part of the film.
- Insufficient development.
- Make sure the film is completely immersed in the detector.
---------------------------------
- Light circular spots on negatives and light on slides.
- Air bubbles.
- Tap the tub gently to expel air bubbles as development begins.
- ... ---------------------------------
- Wide spots with lighter density in the middle than at the edges.
- Signs of drying.
- Use a wetting agent in the last wash water. Squeeze the wet film.
---------------------------------
- Gelatin made with a mesh.
- Wrinkling.
- Pass the film through solutions of different temperatures.
---------------------------------
- Violet color on the film.
- Anti-halo renewal.
- Move the film in a solution containing sulfates, then wash and dry it.
---------------------------------

◾ Some useful tips:
- Hold the machine correctly and press the button slowly to avoid movement.
- Be careful not to put your finger in front of the lens or in front of the bosometer window (external) while taking the picture.
- Fill and empty the machine indoors or in the shade.
- In a 35 mm machine, watch the film sticking and make sure that the film winder rotates during feeding.
- In cold, dry weather, feed the film slowly to avoid breaking it.
- Make sure that the lens of the machine is not exposed to sunlight.
- When entering a warm room from outside, make sure that there is no steam on the lens.
- Place the machine and films in a cool place.
- Do not trust a treatment solution that has been used before. If in doubt, throw away this solution and prepare a new one.
- Never cut 110 film images into individual negatives.
- Store negatives and positive slides in a dry place.

الفشل - التعرف على الأخطاء وتصحيحها .. اختيار واستخدام المواد .. كتاب التصوير الضوئي

الفشل - التعرف على الأخطاء وتصحيحها .. اختيار واستخدام المواد .. كتاب التصوير الضوئي

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