Thursday, February 19, 2026

Sticky Shed Syndrome & Baking Video Tapes

What is Sticky Shed & Umatic?

Umatic, or 3/4” inch debuted in 1971, making it the first ever video cassette. Its portability and broadcast-standard quality positioned it as the best format for making and sharing video. Used inside broadcast television studios, by video artists and filmmakers - counterculturally and within the mainstream, U-matic is one of the most ubiquitous video formats. 


U-Matic tapes are currently rated as Endangered – 4 (out of 5) for obsolescence. Under good storage conditions, they are suggested to have a 50 year life-span, with the earliest U-matic tapes (1971) already beyond that life. The most significant reason for endangerment is Sticky Shed Syndrome, a degradation issue which can hinder playback. These tapes are at significant risk for loss and should be migrated within a decade. Understanding sticky shed and its remediation process known as “baking”  is essential to informed preservation and collection care to ensure the playability of these tapes for the long run. 

How much time do we have?

In 1995 conservation publications gave magnetic tape 10 - 30 years more of playability (Van Bogart, 1995; Image Permanence Institute, 1996). In 2010, Crystal Sanchez cited popular sentiment in her MIAP thesis that there were 15 years left. The common “degralescence” narrative forwarded by Mike Casey pushed for quick migration to new formats, seeing the impending end of life for Umatic. 

Currently, U-matic tapes are rated a 4 out of 5 on the Museum of Obsolete Media’s Obsolescence rating. 4 indicates that the format is endangered, or high risk. Equipment capable of reading the media may be increasingly rare, or difficult or expensive to maintain.

However, here we are in 2026, with completely playable tapes. In 2002, Jim Wheeler declared tapes can last well over 50 years if stored well (Wheeler, Video Preservation Handbook, 2002). As Peter Brothers of Specs Bros says: 

Instead of a countdown clock, we it's imperative we take this approach.

I have personally found that most tapes are entirely playable if you have the patience and creativity. Baking is a key tool and a deep understanding of the composition of tape and the science of baking enables us to hone workflows, take risks within known limits, and get better results. 

From the library of congress: 

Source: CLIR Accelerated Aging of Polyester-Based Legacy Audio Magnetic Tape Stock

We will always approach a tape with that mentality, digitizing a tape several times to try to get the best possible image. Most vendors, working on deadlines and without an attachment to the content simply don’t digitize with that approach.



Magnetic Tape Composition

Magnetic Tape is made up of a PET plastic base (the tape), binder (glue), and magnetic particles. The tape is a flexible, clear plastic PET. It is very stable plastic compound and stored out of UV and heat is quite robust. 

The binder is the biggest issue for tapes. Think of the binder like Jell-O where it is holding or suspending the items inside the jell-o mold, in this case the magnetic particles and reservoirs of lubricant and dispersant. 

Much like Jell-O the binder is susceptible to decay because it is organic. Most people assume that the plastic backing tape itself is vulnerable, but it is far more robust than we assume. 

“The organic materials contained in the magnetic coating of current tape inherently and unavoidably are susceptible to change, degradation, migration and exudation over time, dependent on storage conditions.” - Ampex Patent (1989)

The binder is made of up of three key components: the polymer chains, lubricants, and dispersants. 

Polymers are the chains of molecules that represent a particular synthetic poly-plastic blend. Some common examples used in videotape include polyesterurethane and polyestherurethane. Polymers have a large molecular weight and a strong bond.

Dispersants allow the particles contained inside the binder to remain separate rather than cross-linking. This is particularly important for the magnetic particles to prevent them from clumping together. Think about how if you put oil and soap in water, the soap will naturally break up the oil in smaller bubbles.

Lubricants prevent the tape from sticking to the drum or rollers. Lubricant is stored in “reservoirs” or small deposits in the binder. Lubricant loss is similarly a quoted issue in videotape playback.


Sticky Shed Syndrome or Binder Hydrolysis

Hydrolysis is a chemical reaction whereby the addition of water splits apart a compound from a larger string of molecules to smaller ones. A common example is with food - a carbohydrate is broken down by water, turning it into sugar molecules, for example Sucrose → glucose + fructose.

The poly-esther-urethane / poly-ester-urethane compound making up the binder has strong molecular chains. With the addition of water molecules from the ambient environment, the linkages are broken. The broken links form oligomers or smaller units that are lower in weight and have weaker bonds. The Oligomers migrate from the plastic base, and with them so do the magnetic particles, the lubricant, and dispersants contained within the binder. 

Using molecular weight, we can actually see this process in action. This graph from a CLIR study between FujiFilm & Library of Congress, they mapped binder molecular weight. For tapes with sticky shed (black / open diamond), the count of lower weight molecules was significantly higher compared to non-sticky (black / closed diamond).

Source: CLIR Accelerated Aging of Polyester-Based Legacy Audio Magnetic Tape Stock

Under a microscope, the shedding is quite visible.


Source: LOC “Towards understanding the thermal remediation of degraded archival reel-to-reel audio tapes”


Source: CLIR Accelerated Aging of Polyester-Based Legacy Audio Magnetic Tape Stock

Detecting Sticky Shed

Brand > Environment

Manufacturer brand and batch is by far the biggest indicator of sticky shed syndrome, far more than environmental conditions. This is because sticky shed is a manufacturer fault and appears almost concurrently with manufacture. With age and environmental conditions, the sticky shed worsens, not uniquely introduced.

As a FujiFilm & Library of Congress Study demonstrated, it was not environmental conditions alone which produced unplayability for tapes, it was defects inherent to manufacturing batches with created issues.

Richard Hess, who primarily works with audio tape wrote: 

Tracking Brand Metadata

First and foremost - always remove the red tab in the back of umatic. This prevents the tape from accidentally being recorded over!!

During cataloging and inspection the following information should be collected to best predict sticky shed issues:

  • Brand

  • Recording Code (often beginning with a K or U)

  • Size (Small or Large)

  • Recording Style (Superior Play, High Band, or Low Band) 

  • Color of the shell & door

The brand can often be found on the case, the face of the cassette, or the cassette door. However, some tapes are unbranded and you need to also track the color of the shell and the door. This is a major indicator of manufacture batch and can also help with identification of unmarked tapes. 

Always Bake


Sometimes Bake

Rarely Bake

Cannot Bake

Acetate (brown tape, translucent when held to the light)






ME Tapes

Signs of Sticky Shed

Interwrap Adhesion - Turn Test

You can also detect sticky shed prior to playback using the turn test. Stick a pencil in the holes of the reels and see if you can turn the tape with ease. If not, the tape has sticky shed.

This only works for U-matic because there are no locking mechanisms in the reel, unlike VHS which has locks. You can use a pencil or a specialized piece of 3-D printed plastic to unlock the reels to test it. You can turn the reels with a sharpie cap or a rewind key! 

Slip-Stick Playback

A clear indicator of sticky shed is increased fiction in the tape path, known as Slip-Stick Playback. It means that the tape is sticking to itself causing the friction and tension in the tape path to increase.
The following graph shows the Coefficient of Friction, clearly increasing in an erratic pattern for the sticky shed tape.

Source: CLIR Accelerated Aging of Polyester-Based Legacy Audio Magnetic Tape Stock 

Most Umatic decks have automatic stop functions for when the deck detects high tension loads. It will usually read out as a tension error, most commonly ERR-02 but check your specific deck. Here’s what slip-stick looks like for a tape that will actually advance. 

Source: Sticky Shed Syndrome on U-matic Demonstration

Squealing

Squealing is a symptom most common with audio tapes subject to sticky shed. It is the result of exudations of lubricant from the tape.

Source: NOS Scotch/3M 966 gone sticky

Shed

Shed can be dramatic - a complete breakdown of the binder can result in the magnetic particles completely detaching from the tape in large sheets (seen below with audio tape). 


For Videotape, shed is often release inside the chassis and directly into the video drum.

Head Clog

Head clog is when the video heads that read magnetic fluxes become clogged with dirt, debris, or shed, causing information loss. For Umatic tapes, progressive bands of static begin to fill the screen, eventually leading to full drop out of color and picture. Often times, the image is jumpy and cannot be stabilized. 

Source: BAVC Preserve “AV Artifact Atlas”

Source: Austrialian Television Archive


For VHS, head clog is slightly less progressive. It can often appear as jumping frames or a lack of stabilization.

This VHS tape was suffering from sticky shed syndrome. It prevented the tape from correctly being decoded and stabilized inside the TBC. This tape was quite dirty and required several rounds of cleaning. 


Dirty tape, causing head clog in the middle of a transfer.
 


Recipes

The imprecise nature of baking means that there are dozens of different formulations for baking. In 1989, Ampex put out a patent for baking tapes at 54°C for 16 hrs. There is is something particular about 54°C that is the turning point for tapes to enter a phase change.


How chemistry can save sounds of the past

UCLA Film & Television Archive, Digital Lab

At the Digital Lab we are lucky enough to have Randy who experimented with baking early. He first began with experiments leaving a tape in a hot car - allowing the tape to warm in the direct sun for several hours. He also brought in his mom’s vintage bun warmer to heat the tapes up. The principles are the same - warming under hot dry conditions can improve playability. Additionally, you can keep a tape running right before playback in a warm deck to improve its playability.


Today in the Digital Lab at the UCLA Film & Television Archive, we bake at 57°C (135°F) for 34 - 96 hours. We have baked up to a week (7 days). The oven we use is a 160L 24 Tray Weston Brand oven. The reason Lauren (Digital Lab Staff) chose this oven was because it can fit 1” Videotape Reels, unlike many of the desktop models. This model is no longer for sale, but there are several others that are 160L. This model bakes up to 24 hours so it needs to be restarted once a day.

We do not have an RTI tape cleaner so we use a working deck in the 5000 series because we have dozens of them and they are only low band, so cannot play all tapes. After baking, the tapes cool for 12-24 hours in the oven as it cools down. Then tapes can be played or cleaned in the cheap deck. 

UCLA Library Special Collections, AV Preservation

AV Preservation bakes tapes at 55°C (131°F) for audio cassette 12 - 16 hours. For Umatics and 1/2” Open Reel 55°C (131°F) for 72 hours minimum. They use a Thermocenter Scientific Oven. They also clean tapes with an RTI tape cleaner.



Bay Area Video Coalition 

“We found that method that yielded the best results for sticky and dirty ½” Open Reel EIAJ and ¾” U-matic tapes was baking tapes for 48 hours at 125.6˚F (52˚C). The following is the program that BAVC uses for our SalvisLab Thermocenter scientific oven:

Program Name: P02
Set Temp: 52℃
Gradient: 4,0℃/min
Hold Time: 48:00 [48-hour cycle]
Fan Speed: 60%”

Duke University Libraries

“[…] we always bake (dehumidify) our U-matic videotapes in a scientific oven at 52 celsius (125 fahrenheit) for at least 10 hours. Then we run each tape through a specialized tape-cleaning machine, which fast-forwards and rewinds each tape, while using a burnishing blade to wipe off any built-up residue. We also clean the video heads inside our U-matic decks before each playback, using denatured alcohol.”

Source: U-matic for the People (2019)

MMCC Collection

Additional Recipes and Documentation for other archives from the Magnetic Media Crisis Committee.
For scientific ovens:
Mean = 25 hrs
Mode = 24 hrs
Range = 7 - 72 hrs
Mean = 47.5 °C
Mode = 52 °C
Range = 40.5°C - 60°C My assessment of these recipes is that they are generally too low heat and too short. They are likely out of date a bit.

Recommended Ovens

Cost doesn’t necessarily improve performance. A consumer grade dehydrator is totally sufficient for baking. The factors you want to consider are:

  1. Cost

  2. Timer Max Duration

  3. Wattage

  4. Number of Trays

  5. Capacity in L

In the digital lab, we use the Weston 160L 24 Tray Commercial Dehydrator. 160L is essential for digitizing 1” reels, which you cannot do in a countertop model. The one issue is the timer has to be reset once a day, which means we cannot bake over the weekend. 

At TAPE, we selected the Excalibur Food Dehydrator which is $180 and has up to an 80 hour timer, meaning I can set it for a few days. 

  1. Cosori Food Dehydrator - $143, 48 hour timer. Used at MiPops

  2. Excalibur Food Dehydrator $210, 26 hr timer. 

  3. Yashe Food Dehydrator, $161, 80 hr timer (another model TAPE considered)

  4. LEM Food Dehydrator, $150 (unknown timer time) Used at CUNY-TV

The schedule that Lauren in the digital lab follows is - Monday - Wednesday Bake; Thursday cooldown ; Friday Digitization. She doesn’t like to go longer that a day or two after baking to digitize. AV Preservation in UCLA Library only cools for a few hours and then immediately digitize.

While you can re-bake a tape, it isn’t recommended as it can cause dropouts.


Baking Results

One of the most important things to know is that baking is an incredible stable process. The Library of Congress FujiFilm Study showed that tapes left at 60°C (way above baking temp) and at very low RH (Relative Humidity) for a year were still playable.


Source:  Richard Hess

When you dehydrate / heat a tape, it results in a re-solubulizing of the polymers, basically a reformation of the glue on the tape. Under a microscope, we can literally see this process happen. 


Again, here is a photo from the library of congress study showing how post baking (right) we see these blemishes remelt into itself Source: LOC “Towards understanding the thermal remediation of degraded archival reel-to-reel audio tapes”


Source: LOC “Towards understanding the thermal remediation of degraded archival reel-to-reel audio tapes”

Another great example of the before and after in digitization demonstrates how easily the tape on the left could be marked as unplayable. 


These examples come from T.A.P.E. - for VHS tapes that were previously unable to be stabilized, baking allowed the time base corrector to properly read the information and reconstruct the image. 





Additionally, baking is an essential tool for mold remediation. Baking tapes at 3 hours for 140°F (60°C) kills active mold spores and dries it out, making it easier to clean the tape. You can read more about identifying and handling mold in Olivia Lindlsey’s Blog on the topic.

Cleaning Tapes

There are a few ways to clean tapes after you’ve baked them. 

  1. Play the tape all the through in a junk deck. This will allow the tape to shed it’s gunk into the junk deck (5000 Umatic Series is great)

  1. You can use a 3-D printed motorized cleaner. I’ve used both the VHS is life cleaner and the 4Mob cleaner. The tape path is a little longer on the 4Mob which I like, plus it has more attachments for more formats. But I do really like the VHS is life and I think it works well. For both you just have to make sure to use a non-abrasive pad and 99% alcohol. Move it very slowly under heat or a fan so it can dry the alcohol before it wraps up onto itself or it will stick.

  1. You can also put open reel video or audio on manual rewinds and clean that manually, although it can be labor intensive.

  1. If you have access to an RTI tape cleaner, this is the best thing for tapes. The diamond tip head gently scrapes the most outer layer of the tape, removing only the dirt and debris. 

Cleaning Video Heads

As we saw in the section on Head Clog, that is the most persistent issue with sticky shed. But is also the most common error in all digitizations, meaning that for all Umatic captures, the heads should be cleaned after every transfer / use of the deck. Use a TEK wipe - the TX1109 Non-abrasive - and saturate it in 99% or 97% Isopropyl alcohol. 


Gently lay the wipe perpendicular to the drum with one hand. Gently spin the drum with your other. Under your fingertips as you hold the wipe flush to the drum you should feel a small indent of the opening to the heads. Gently press into the video heads as you continue moving the drums. Stop if you feel any resistance or pulling. After a few seconds turning, pick up the wipe and move to a different spot. You’ll clean until the wipe comes up clean. 

Shell Swap

Sometimes the shell itself can pose a problem in digitization. The older shells can loose their ability to advance tapes successfully. Keep around an extra empty shell for a later Sony Umatic tape and use that in case a baked tape won’t play. I would not recommend baking the tape in this shell just so you can keep the plastic stable.


Storage

This is a good news / bad news kind of a question. Despite common misconceptions, it is NOT storage alone which creates sticky shed issues. While very poor storage can worsen sticky shed and environmental conditions can make lower temperature baking less effective, just bad storage will not result in sticky shed. 

As the Library of Congress / FujiFilm study found, accelerated aging (high temps / high humidity) did not introduce unplability to sticky shed syndrome tapes. According to their predictions, it would take 100 years at “office temperature” to cause playback issues. Slightly below room temperature is an ideal storage condition for tapes. Too cold can introduce more moisture than needed. Therefore, tapes at room temperature should not be of high concern.



The bad news is that cold storage will not slow decay. Unlike film, videotape does not benefit from cold storage conditions. Therefore, better storage doesn’t necessarily extend the life of videotape, it must be migrated.

Sources & Further Reading

OVERVIEWS & PRESENTATIONS

WHITE PAPERS / PUBLICATIONS

ADDITIONAL RESOURCES

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