Identification and Prevention of Appearance Defects in Radiographic Examination Films Beyond Artificial Defects

Release Date:

2022/06/10

I. Image of Pressure Marks 1. What is the surface manifestation of pressure marks? Pressure marks are characterized by a density significantly lower than that of the surrounding areas. 2. What causes them? Localized, severe mechanical stress on a particular area of the film prior to exposure. 3. When might these phenomena occur? The primary cause of pressure marks lies in improper handling of the film during darkroom preparation. During processing, a specific area of the film may become compressed (clamped) within the dark bag. Objects falling onto the dark bag can also produce pressure marks. 4. How can pressure marks be identified? Carefully prepare another darkroom film from the same package, expose and develop it; if no defects similar to those observed the first time are found, the spots seen initially are very likely pressure marks. 5. How can pressure marks be prevented? Strictly adhere to darkroom operating procedures, handle the film with care at all times, and avoid applying any kind of pressure to it. II. Image of Post-Exposure Creases 1. What is the surface manifestation of creases (post-exposure)? Creases are characterized by black crescent-shaped marks with higher density than the adjacent film areas (greater optical density). 2. What causes post-exposure creases? Over-bending or forceful bending of the film during or after exposure, or during processing, will result in creases. 3. When might these phenomena occur? Post-exposure creases typically arise when the film is improperly handled during removal from the dark bag or when loading it into the developing tray. 4. How can post-exposure creases be detected? Expose several films, then deliberately roll or twist them, develop them, and examine the negatives under reflected light; you may observe one or more crescent-shaped black marks. 5. How can post-exposure creases be avoided? Strictly follow darkroom operating procedures, handle the film with care at all times, and especially avoid applying any pressure to the film with your fingers. III. Pre-Exposure Creases 1. What is the surface manifestation of creases? Pre-exposure creases are characterized by white crescent-shaped marks with lower density than the surrounding film areas (lower optical density). 2. What causes them? Excessive or abrupt bending of the film before exposure can lead to this type of crease. 3. When might these phenomena occur? They usually appear when the film is improperly handled upon removal from the package or when being loaded into the dark bag prior to exposure. 4. How can pre-exposure creases be identified? Deliberately roll or twist certain films, expose them, and then develop them as usual. Upon examination, you may find fainter-colored creases in areas where the film was mishandled. 5. How can they be avoided? Strictly adhere to darkroom operating procedures, handle the film with care at all times, and especially avoid applying any pressure to the film with your fingers. IV. Fixer Stains 1. What is their surface manifestation? Stains caused by fixer solution appear as small white circular spots with lower density than the surrounding film areas. 2. What causes them? Even trace amounts of fixer solution splashed before development can lead to the formation of white spots. 3. When might these phenomena occur? Whenever chemical contamination is present, this phenomenon may occur. It most often results from improper darkroom layout or careless processing. 4. How can they be avoided? Ensure that the film-handling area is safe, dry, and clean, and prevent fixer solution from splashing onto the film. V. Developer Stains 1. What is their surface manifestation? Stains caused by developer solution also appear as small circular spots, but with higher optical density than the surrounding film areas. 2. What causes them? Touching the film or developer solution splashing onto it before rinsing can lead to this type of stain. 3. When might these phenomena occur? Improper darkroom layout or careless processing can both result in such stains. 4. How can they be avoided? Prevent any chemical solutions from splashing, and ensure that the film-loading area is completely dry. VI. Intensifying Screen Marks 1. What is their surface manifestation? Intensifying screen marks appear as a dark line on the negative; they may also manifest as white spots on the negative. 2. What causes them? Dark lines are caused by deep abrasions on the lead foil intensifying screen, while bright spots result from flaky impurities on the lead foil intensifying screen. 3. When might these phenomena occur? When the lead foil intensifying screen suffers some degree of abrasion or damage, you will see scratches on it; if impurities get trapped on the surface, this phenomenon will also occur. 4. How can marks on the lead foil intensifying screen be detected? Carefully inspect the lead foil intensifying screen up close; if any damage is found, it must be replaced. If it is unclear whether damage has occurred, replace the suspected lead foil intensifying screen with a new one and then test using film. 5. How can they be avoided? First, avoid scratching the lead foil intensifying screen and keep the working area clean at all times. In addition, if possible, use film packaged in lead-sealed containers. VII. Paper Interference Marks 1. What is their surface manifestation? Paper interference marks appear as a low-density area that nearly covers the entire film. 2. What causes them? If a sheet of paper is interposed between the film and the lead foil intensifying screen and casts a shadow, paper interference marks will appear. 3. When might these phenomena occur? This happens if the backing paper is not removed. 4. How can paper interference marks be detected? Simply perform exposure tests both with and without the backing paper. 5. How can they be avoided? Ensure that all backing paper is removed before exposure. VIII. Edge Bite Images IX. Electrostatic Exposure Spots 1. What is the surface manifestation of electrostatic exposure spots? Electrostatic exposure spots are characterized by jagged, branching black lines or irregular, densely packed small black dots. 2. What causes electrostatic exposure spots? The dispersal of static electric charges leads to electrostatic exposure spots. 3. When do electrostatic exposure spots occur? The most common cause is rapidly removing the film from the package in relatively low-humidity (dry) conditions. 4. How can electrostatic exposure spots be detected? If you walk slowly or run your hands through your hair before handling the film, you may sometimes see or hear static discharge. If you notice jagged lines or black spots on the developed film, it is highly likely that electrostatic exposure spots have appeared. 5. How can they be avoided? Store the film in an environment with relative humidity above 40%, and avoid quickly sliding or moving the film when taking it out of the package. X. Concave Images XI. Excuse Pit Images

I. Indentation Images

            1. What is the surface phenomenon of an indentation?
The indentation is characterized by a density that is significantly lower than that of the surrounding region.
            2. What are the causes of their occurrence?
A specific area of the film experiences severe localized stress prior to exposure.
            3. When might these phenomena occur?
The primary cause of pressure marks is improper handling of the film during dark-bag preparation. During processing, a particular area of the film may become compressed (clamped) within the dark bag. Objects that fall onto the dark bag can also result in pressure marks.
            4. How to inspect the indentation?
Carefully prepare another undeveloped film sheet directly from the same packaging box, expose it, and develop it. If no defects identical to those observed the first time are found, the marks seen initially are very likely pressure marks.
            5. How to avoid indentation?
Strictly adhere to darkroom operating procedures and handle film with utmost care at all times, ensuring that no pressure of any kind is applied to the film.

II. Crease Images After Exposure

            1. What is the surface phenomenon of the crease (after exposure)?
The crease is characterized by a black crescent-shaped appearance, with a higher density than the adjacent film area (higher optical density).
            2. What causes creases (after exposure)?
Overbending (or bending too forcefully) the film after exposure or during development can cause creases to form on the film.
            3. When might these phenomena occur?
Creases (after exposure) typically occur when film is mishandled during removal from the light-tight bag or from the film holder.
            4. How to detect creases after exposure?
Expose some film, then deliberately curl or twist it; develop the film, and examine it under reflected light—you may observe one or more crescent-shaped dark marks.
            5. How can creases be avoided (after exposure)?
Strictly adhere to darkroom operating procedures and handle film with utmost care at all times, taking special precautions to avoid applying any pressure to the film with your fingers.

III. Pre-exposure Crease Image

            1. What is the surface phenomenon of creases?
Before exposure, the crease appears as a white crescent-shaped area with lower density than the adjacent film region (lower optical density).
            2. What are the causes of their occurrence?
Excessive or abrupt bending of the film before exposure can result in this type of crease.
            3. When might these phenomena occur?
This typically occurs when the film is mishandled upon removal from the packaging box or when it is loaded into a light-tight bag prior to exposure.
            4. How to inspect pre-exposure creases?
Consciously curl or twist certain film rolls to expose them, then develop them as usual. Upon inspection, you may notice faint, color-bleached creases in areas where the film was mishandled.
            5. How can they be avoided?
Strictly adhere to darkroom operating procedures and handle film with utmost care at all times, taking special precautions to avoid applying any pressure to the film with your fingers.

IV. Fixer Stains

            1. What is their surface phenomenon?
The spots produced by the fixer are characterized as small white circular dots with a lower density than the surrounding areas of the film.
            2. What are the causes of their occurrence?
Even trace amounts of developer solution that splash out before development can potentially cause white spots to form.
            3. When might these phenomena occur?
This phenomenon can occur whenever chemical contamination is present. It most often results from improper darkroom layout or careless processing.
            4. How can they be avoided?
Ensure the film loading/unloading area is safe, dry, and clean; do not allow fixer to splash onto the film.

V. Developer Stains

            1. What is their surface phenomenon?
The spots produced by the developer also appear as small, round dots, but their density is higher than that of the surrounding film area.
            2. What are the causes of their occurrence?
Before film development, touching the film or splashing developer can both lead to the formation of this type of spot.
            3. When might these phenomena occur?
Improper darkroom layout or improper developing can both lead to these spots.
            4. How can they be avoided?
Do not allow any type of chemical solution to splash; ensure that the film-loading area is completely dry.

VI. Scars from the Intensifying Screen

            1. What is their surface phenomenon?
The manifestation of intensifying-screen artifacts is a dark line on the negative, but they may also appear as white spots on the negative.
            2. What are the causes of their occurrence?
Dark streaks are caused by deep scratches on the lead-film intensifying screen, while bright spots are caused by flaky impurities on the same screen.
            3. When might these phenomena occur?
When the lead-film intensifying screen is subjected to a certain degree of scratching or damage, you will observe scratches on the screen; this phenomenon can also occur if impurities get embedded in it.
            4. How to detect traces on lead-film intensifying screens?
Carefully inspect the lead-film intensifying screen at close range; if any damage is found, it must be replaced. If it is uncertain whether damage has occurred, replace the suspected lead-film intensifying screen with a new one and then perform film inspection.
            5. How can they be avoided?

First, avoid scratching the lead-foil intensifying screen and always keep the work area clean. In addition, if possible, use film packaged in lead-sealed containers.

VII. Traces of Paper Jam

            1. What is their surface phenomenon?
The evidence of paper-clipping is manifested as a low-density area that nearly covers the entire film.
            2. What are the causes of their occurrence?
If a sheet of paper is present between the film and the lead-film intensifying screen, causing a projection, a paper‑trap mark will appear.
            3. When might these phenomena occur?
This will happen if the backing paper is not removed.
            4. How to detect paper jam marks?
Simply perform exposure testing in both lined and unlined conditions.
            5. How can they be avoided?
Ensure that all backing paper is removed before exposure.

VIII. Undercut Imaging

9. Electrostatic Exposure Spots

            1. What is the surface phenomenon of electrostatic exposure spots?
Electrostatic exposure spots are characterized by jagged, branched black lines or irregular, densely packed small black dots.
            2. What causes electrostatic exposure spots?
The diffusion motion of electrostatic charges leads to electrostatic exposure spots.
            3. When do electrostatic exposure spots occur?
Under conditions of low relative humidity (dry air), rapidly removing film from its packaging is the most common cause of electrostatic exposure spots.
            4. How to detect electrostatic exposure spots?
If you walk slowly or run your fingers through your hair before handling the film, you may sometimes see or hear a static discharge. If you notice jagged lines or black spots on the developed film, it is highly likely that static exposure marks have appeared.
            5. How can it be avoided?
Store film in an environment with relative humidity greater than 40%, and avoid rapidly sliding or moving the film when removing it from the packaging box.

X. Concave Image

XI. Image of the Excuse Pit

This website reprints content originally published by our editorial team for the purpose of disseminating additional information; such reprinting does not imply endorsement of the views expressed or responsibility for the accuracy of the content. If the content involves issues related to intellectual property, copyright, or other matters, please contact us within 30 days, and we will promptly remove the relevant material.

Phased Array Ultrasonic Testing of Compressor Bolts

Differences in Ultrasonic Testing Methods for Castings and Forgings

Phased Array Ultrasonic Testing of Compressor Bolts

Differences in Ultrasonic Testing Methods for Castings and Forgings

To further carry forward the spirit of Lei Feng and promote the volunteer ethos of “dedication, friendship, mutual assistance, and progress,” in accordance with the spirit of the Henan Provincial Association for Science and Technology’s “Notice on Launching a Centralized ‘i-Science Popularization’ Science and Technology Volunteer Service Campaign in the Spirit of Lei Feng,” Luoyang Weicheng Engineering Testing Co., Ltd. responded enthusiastically to the call and organized a science popularization event on the safe operation of forklifts. On March 4, our company meticulously planned and conducted an emergency response drill for special equipment—forklift accidents—and invited several nearby companies that use forklifts to observe the exercise. The purpose of this drill was to simulate real-world working conditions, specifically the sudden occurrence of an accident during the process of using a forklift to handle goods.

2024-03-05

The 10th Anniversary Gratitude Celebration of Luoyang Weicheng Engineering Testing Co., Ltd. Concludes Successfully

On the afternoon of December 29, 2023, Weicheng Testing Co., Ltd. held a grand gratitude celebration—“Our Ten Years”—inviting distinguished guests, including Mr. Jia Hong, Director and Vice Chairman of the Titanium-Zirconium Industry Development and Application Center of the China Equipment Management Association, as well as Mr. Lu Fusheng, Executive Deputy Director, Vice Chairman, and Secretary-General, along with clients and partners, to jointly witness this milestone occasion. The first segment of the event: A Decade of Development The event officially commenced at 2:00 p.m., with the company welcoming all attendees

2024-01-11

In 2023, Luoyang Weicheng Engineering Testing Co., Ltd. Successfully Held the “Intensive Training and Competition” — Gamma-Ray Radiographic Inspection Emergency Drill

On October 11, Luoyang Weicheng Engineering Testing Co., Ltd. held a large-scale training and competition—specifically, a γ-ray radiographic inspection radiation emergency response drill—under the theme “Everyone Talks About Safety, Everyone Knows How to Respond to Emergencies.” The event invited leaders from the provincial, municipal, and district levels to attend and observe. Prior to the start of the emergency response drill, Cui Songbiao, General Manager of Luoyang Weicheng Engineering Testing Co., Ltd., and Gong Aifeng, Deputy General Manager, extended a warm welcome to the visiting provincial, municipal, and district leaders and pledged that Weicheng Testing would consistently focus on enhancing its professional technical expertise and emergency response capabilities as key drivers for corporate safety management.

2023-10-19

Return to list

Address: Room 104, Building 9, Futong Intelligent Manufacturing Industrial Park, Jinye 1st Road, Yiyang County, Luoyang City, Henan Province

Phone:+86-379-66915081 +86-379-66915005

Email:lywcjc@lywcjc.cn

Fax:+86-379-66919852

Website:www.lywcjc.cn

WeChat

Yu Public Security Bureau Filing No. 41030602000129

COOKIES

Our website uses cookies and similar technologies to personalize the advertising shown to you and to help you get the best experience on our website. For more information, see our Privacy & Cookie Policy

COOKIES

required

These cookies are necessary for basic functions such as payment. Standard cookies cannot be turned off and do not store any of your information.

analyze

These cookies collect information, such as how many people are using our site or which pages are popular, to help us improve the customer experience. Turning these cookies off will mean we can't collect information to improve your experience.

Feature

These cookies enable the website to provide enhanced functionality and personalization. They may be set by us or by third-party providers whose services we have added to our pages. If you do not allow these cookies, some or all of these services may not function properly.

advertise

These cookies help us understand what you are interested in so that we can show you relevant advertising on other websites. Turning these cookies off will mean we are unable to show you any personalized advertising.