Is digital radiography faster than conventional film for pipeline welds?

Yes. On a representative 24-inch girth weld, conventional film takes about 57 minutes to a usable image, roughly 12 minutes of exposure plus 45 minutes of darkroom development, versus about 10 minutes read on screen for digital. That is over 5 times faster to an accept/repair decision.

How long does radiographic exposure take by pipe diameter?

Typical exposure time, digital versus conventional film: 10 to 12 inch about 1 minute vs 3 minutes; 16 inch about 5 minutes vs 3 to 5 minutes; 20 inch about 8 minutes vs 5 to 10 minutes; 24 inch about 10 minutes vs 8 to 12 minutes; 30 inch about 12 minutes vs 12 to 16 minutes. Every conventional exposure then adds 45 minutes of film development, for a film total of about 48 minutes at 10 to 12 inch, 48 to 50 minutes at 16 inch, 50 to 55 minutes at 20 inch, 53 to 57 minutes at 24 inch, and 57 to 61 minutes at 30 inch. Digital has no development step, so it is faster than film's total time at every size, from about 5 times at 30 inch up to about 48 times at 10 to 12 inch.

Digital vs Conventional Radiography: Exposure & Speed

Q: Why is conventional film radiography slower than digital?

Conventional film carries about 45 minutes of darkroom development on top of every exposure, and the image is not usable until it is out of the darkroom. Digital radiography is read on screen with no development step, so the crew never stops for a darkroom.

Digital and conventional radiography read a similar image, but they reach a usable result on very different clocks. Conventional film carries darkroom development on top of every exposure — and on a construction spread, that time is the whole story.

Exposure is only half of film’s clock.

Representative time to a readable result on a 24-inch girth weld — the exposure, plus the 45 minutes of film development that digital simply does not have.

Time to an accept/repair decision — 24" weld

Representative figures for a 24" weld; exposure varies with diameter and wall (see table). The 45-minute development applies to every conventional exposure — the image is not usable until it is out of the darkroom.

Radiographic time to a usable image, per weld.

Film's clock does not stop at exposure — every exposure adds 45 minutes of development before the image is usable. Digital has no development step, so its exposure time is its total time. Add development in, and digital wins at every pipe size.

Pipe diameter	Digital (total)	Film exposure	Film development	Film total	Digital advantage
10"–12"	1 min	3 min	45 min	48 min	48× faster
16"	5 min	3–5 min	45 min	48–50 min	~9.6–10× faster
20"	8 min	5–10 min	45 min	50–55 min	~6.2–6.9× faster
24"	10 min	8–12 min	45 min	53–57 min	~5.3–5.7× faster
30"	12 min	12–16 min	45 min	57–61 min	~4.8–5.1× faster

Film total = exposure + 45 minutes of development. Digital advantage = film total ÷ digital time, computed directly from the columns to its left.

Every conventional exposure adds 45 minutes of film development before the image is usable — digital has no development step. Counted in, digital is faster at every pipe size: from about 4.8–5.1× on 30" welds up to 48× on 10"–12" welds. On a representative 24" weld that is 53–57 minutes total versus 10 minutes read on screen for digital — over 5× faster to an accept/repair decision (24" example, including film development), and the crew never stops for a darkroom.

Digital wins before the film even hits the developer.

Exposure is only half of film’s clock.

Radiographic time to a usable image, per weld.

Related resources.

Need radiography, ultrasonics, or both?

Digital wins before the film even hits the developer.

Exposure is only half of film’s clock.

Radiographic time to a usable image, per weld.

Related resources.

Automated ultrasonic testing →

Heavy-wall weld inspection →

AUT vs radiography →

Need radiography, ultrasonics, or both?