Matlab writes an empty multipage tiff. Why?

Hello Everyone,

I have a Variable C with dimensions of 391x1024x141. It was read and put together from several tiff files. Loading the tiff files I get these informations:

info.Filename, info.FileModDate, info.FileSize, info.Format, info.FormatVersion, info.Width, info.Height, info.BitDepth, info.ColorType, info.FormatSignature, info.ByteOrder, info.NewSubFileType, info.BitsPerSample, info.Compression, info.PhotometricInterpretation, info.StripOffsets, info.SamplesPerPixel, info.RowsPerStrip, info.StripByteCounts, info.XResolution, info.YResolution, info.ResolutionUnit, info.Colormap, info.PlanarConfiguration, info.TileWidth, info.TileLength, info.TileOffsets, info.TileByteCounts, info.Orientation, info.FillOrder, info.GrayResponseUnit, info.MaxSampleValue, info.MinSampleValue, info.Thresholding, info.Offset, info.ExtraSamples, info.SampleFormat

My Code is this:

NumImages = size(C,3);
for k = 1:NumImages

      imwrite(C(:,:,k),'LII_C2H4_YF100_strain035_45percent_7_wPump_Coflow175.tif','tif','WriteMode','append');

end

It writes the multipage tiff as described, but every Image is just white.

Why?

Thank you in advance