Museum Water Emergency Recovery

Recovery includes activities performed post-response to improve outcomes such as careful handling, rinsing, removing excess water, and drying.

Handling When Wet

When the action of removing objects from the affected environment has finally begun, caution should be taken to reduce the chance of further damage to materials while handling. Objects that have not been wetted should be treated with the same protocols for careful handling as would normally be applied to the materials. Wet objects, however, are now significantly more sensitive to damage. It is important to remember that inkjet print supports can be simple papers that have low wet strength or resin-coated laminates that are much stronger. If the first print recovered appears physically robust when wet, the next may be fragile and tear easily. Wet paper is more likely to tear, fold, or crimp, and surfaces are more likely to abrade or scratch, so loose prints in water should be fully supported from beneath when lifted and afterwards carried individually. On the other hand, wet prints in stacks will be inherently stronger, as their combined strength will higher than for individual sheets. Again, if supported from beneath these can be transferred as a group to the drying area before separation. Wet storage boxes can also be more prone to collapse under the weight of water, so they too should be carried very carefully. The use of carts will help prevent such unnecessary catastrophic failures.

Separation from Stacks and Enclosures

Prints in stacks or enclosures will dry much slower than those dried individually. In addition, drying prints in contact with other surfaces can result in unnecessary further damage including blocking (prints bonding together or to other surfaces), damage to surface sheen (either locally or overall), and continuing colorant bleed or transfer. Prints must be separated from stacks and enclosures before allowing to them dry. This activity should be performed in the rinsing/drying area, as stacks and enclosed wet prints may be sturdier during transport out of the affected area. In addition, prints inside of enclosures may be partially or even completely dry despite the outside of the enclosure being fully inundated with water, so responders must be careful not to drip water from wet boxes or wet prints onto dry prints as they are separated from stacks or removed from housings or frames.

Rinsing

If the offending water was clean, then rinsing will be unnecessary and potentially exacerbate problems. Prints that have been exposed to water containing contaminants such as salt or sediments may require rinsing to remove easily soluble substances and debris. Rinsing should be gentle in clean water. Note that such rinsing will not be done to clean the print only dilute that which is readily soluble as well as remove larger particulates. Cleaning of stains should be delayed until after drying, so energy can be used to salvage as many additional prints as possible. Some contaminants can be harmful, so gloves should be worn. In extreme cases, health hazards may be high enough to warrant immediate and proper disposal of soiled objects. Consultation with official disaster responders may be needed.

Removal of Excess Water

After prints have been recovered from water, and rinsed if necessary, excess water will need to be removed. There are two important reasons for this:

  1. It speeds the drying process as the volume of water needed to evaporate drops dramatically
  2. It reduces the damage to the objects because as long as prints are wet, even after being removed from water, they continue to deteriorate until the moisture content has sufficiently dropped

Unfortunately, for many inkjet print types such attempts may cause unnecessary additional harm. Tilting a print to allow water to run off may result in dissolved ink streaking across the surface of the print. Blotting or wiping can spread water increasing and affected area as well as abrasion or remove surface coatings.

Ink spread, smear, and abrasion

Dye Prints

Wet dye prints on polymer-coated RC paper will be extremely sensitive to any contact. Almost any interaction will spread or smear the colorant and tear the fragile coating on the paper surface. It is best to allow these prints to air dry on their own. Dye prints on fine art papers are less prone to surface damage, but blotting will likely spread the water and exaggerate the area of damage. Unfortunately, if they are not blotted, the water will likely wick laterally across the surface of the print also causing growth in the affected area. Risk and reward of intervention will need to be made on a case by case basis. Dye prints on porous-coated baryta and RC papers can be gently blotted, but with no wiping motion as this may cause smearing. Note too that prolonged blotting can absorb colorant from the papers surface.

Pigment Prints

All pigment prints may be very gently blotted to remove excess water, but no heavy pressure or wiping as the colorant, coating, or papers fibers may be torn away from the surface.

Drying

Is Freezing Safe?

It is best to air dry all wet materials immediately, though if there are too many prints to deal with at once, then freezing prints until safe thawing and drying can take place is an option. However, due to freezer sizes, this option will likely only work for smaller prints, so keep this in mind when managing a major recovery effort.

After prints have been removed from the affected area, rinsed if necessary, and all excess water removed, they are ready for drying.

Proper drying of prints means returning them to natural moisture equilibrium with a recommended storage environment. It does not mean forcing all moisture out of the object as that would result in unnecessary additional damage such as exaggerated planar distortion and cracking of surface coatings. For that reason heat drying objects to speed recovery should never be done. Note that under the above definition, prints that were not wetted but still exposed to high humidity for an extended time, still need to be dried to bring them down to a safe moisture content and prevent dye bleed, blocking, and mold growth.

Prints need to be dried individually, horizontally, and face up. Blotter papers as a support while drying can aid in removal of water from the print, but drying on screens can allow evaporation from both sides of the objects. Drying should not be done in stacks with blotter paper or other interleaves such as spun-bound polyester, as fibers from the blotter may become permanently embedded in the print surface or the texture of the polyester weave may become permanently embossed. In addition, drying prints in stacks may lead to colorant transfer into the blotter paper further damaging the print.

Prints need to be dried individually, horizontally, and face up. Blotter papers as a support while drying can aid in removal of water from the print, but drying on screens can allow evaporation from both sides of the objects.

The relative humidity of the drying environment will affect the rate at which prints dry, but again it will be harmful to dry prints too much or not enough. The optimal range of safe drying will be 30% to 50%, but 20% to 55% may be acceptable. Lower RH will produce faster results, which will reduce the chance of continued colorant bleed and mold growth. The following table can be used as a guide to dry times for different RH values of the drying areas.

Relative Humidity (RH)

Days to Dry

20%

1

30%

1

40%

2

50%

2

60%

3+

Note that the above values are based on the slowest-drying prints types for the most conservative estimate. Some prints, such as those of porous-coated RC paper, may dry much faster.

Post Dry Handling

A final warning should be made. Prints that have been wetted and dried will be different in many ways than they were before the event, even if they look the same. The many subtle changes can include differences in surface sheen, colorant lightening, paper darkening, etc. But in addition to these, there may have also been changes that have made the objects more fragile, and therefore in greater need of sensitive handling after recovery. These effects will be mostly related to the surface coatings used to receive the ink. The coating can be embrittled and more prone to cracking, and they can also be more sensitive to abrasion and scratch. A greater thoughtfulness when providing access to these objects will be needed. It may be worth creating reading room or exhibition surrogates for any print that has shown even the slightest indication of increased fragility. Certainly more robust housings and the use of secondary supports when handling will provide addition security. And finally, addition of notes on this risk to the catalog record and any conservation documentation about the increased sensitivity of these materials will be helpful to everyone that needs access to the object.