diff --git a/.gitignore b/.gitignore
index 9f8204f..e40b6b6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ pkg/
 .ruby-gemset
 fcrepo4-data/
 fcrepo4-test-data/
+coverage/
diff --git a/lib/hydra/derivatives/processors/jpeg2k_image.rb b/lib/hydra/derivatives/processors/jpeg2k_image.rb
index cb4f4b9..1e33965 100644
--- a/lib/hydra/derivatives/processors/jpeg2k_image.rb
+++ b/lib/hydra/derivatives/processors/jpeg2k_image.rb
@@ -73,20 +73,18 @@ def layer_rates(layer_count, compression_numerator)
         rates.map(&:to_s).join(',')
       end
 
-      protected
-
-        def encode(path, recipe, output_file)
-          kdu_compress = Hydra::Derivatives.kdu_compress_path
-          execute "#{kdu_compress} -quiet -i #{path} -o #{output_file} #{recipe}"
-        end
+      def encode(path, recipe, output_file)
+        kdu_compress = Hydra::Derivatives.kdu_compress_path
+        execute "#{kdu_compress} -quiet -i #{path} -o #{output_file} #{recipe}"
+      end
 
-        def tmp_file(ext)
-          Dir::Tmpname.create(['sufia', ext], Hydra::Derivatives.temp_file_base) {}
-        end
+      def tmp_file(ext)
+        Dir::Tmpname.create(['sufia', ext], Hydra::Derivatives.temp_file_base) {}
+      end
 
-        def long_dim(image)
-          [image[:width], image[:height]].max
-        end
+      def long_dim(image)
+        [image[:width], image[:height]].max
+      end
     end
 
     def process
diff --git a/spec/processors/jpeg2k_spec.rb b/spec/processors/jpeg2k_spec.rb
index b33d8d9..acd5951 100644
--- a/spec/processors/jpeg2k_spec.rb
+++ b/spec/processors/jpeg2k_spec.rb
@@ -3,6 +3,8 @@
 
 describe Hydra::Derivatives::Processors::Jpeg2kImage do
   let(:object) { ActiveFedora::Base.new }
+  let(:filename) { File.expand_path('../../fixtures/test.tif', __FILE__) }
+  let(:image) { MiniMagick::Image.open(filename) }
 
   describe "#calculate_recipe" do
     it "calculates the number of levels from a size" do
@@ -54,4 +56,24 @@
       expect(r).to eq(described_class.calculate_recipe(args, 'grey', 7200))
     end
   end
+
+  describe "#encode" do
+    it "executes the external utility" do
+      expect(described_class).to receive(:execute) { 0 }
+      described_class.encode('infile', 'recipe', 'outfile')
+    end
+  end
+
+  describe "#tmp_file" do
+    it "returns a temp file with the correct extension" do
+      f = described_class.tmp_file('.test')
+      expect(f).to end_with('.test')
+    end
+  end
+
+  describe "long_dim" do
+    it "returns the image's largest dimension" do
+      expect(described_class.long_dim(image)).to eq(386)
+    end
+  end
 end
diff --git a/spec/units/transcoding_spec.rb b/spec/units/transcoding_spec.rb
index e2d3216..98d5d5d 100644
--- a/spec/units/transcoding_spec.rb
+++ b/spec/units/transcoding_spec.rb
@@ -58,10 +58,10 @@ def create_derivatives(_filename)
         when 'image/tiff'
           Jpeg2kImageDerivatives.create(self, source: :original_file,
                                               outputs: [
-                                                { label: :resized,       recipe: :default, processor: 'jpeg2k_image', resize: "600x600>", url: "#{uri}/resized" },
-                                                { label: :config_lookup, recipe: :default, processor: 'jpeg2k_image',                     url: "#{uri}/config_lookup" },
-                                                { label: :string_recipe, recipe: '-quiet', processor: 'jpeg2k_image',                     url: "#{uri}/string_recipe" },
-                                                { label: :diy,                             processor: 'jpeg2k_image',                     url: "#{uri}/original_file_diy" }])
+                                                { label: :resized,       format: 'jp2', recipe: :default, processor: 'jpeg2k_image', resize: "600x600>", url: "#{uri}/resized" },
+                                                { label: :config_lookup, format: 'jp2', recipe: :default, processor: 'jpeg2k_image', url: "#{uri}/config_lookup" },
+                                                { label: :string_recipe, format: 'jp2', recipe: '-jp2_space sRGB', processor: 'jpeg2k_image', url: "#{uri}/string_recipe" },
+                                                { label: :diy,           format: 'jp2', processor: 'jpeg2k_image', url: "#{uri}/original_file_diy" }])
         when 'image/x-adobe-dng'
           ImageDerivatives.create(self, source: :original_file,
                                         outputs: [
@@ -318,6 +318,7 @@ def create_derivatives(_filename)
     let(:file) do
       GenericFile.new(mime_type_from_fits: 'image/tiff').tap do |t|
         t.original_file.content = attachment
+        t.original_file.mime_type = 'image/tiff'
         t.save
       end
     end